DRY CELLS

In the daily life there is a variety of Dry Cells. An example of dry cell is the compact form of the Leclanche cell as shown in the picture. This cell usually we call as a battery. As an anode is a cylindrical Zn container. Cathode used in this cell is Central Graphite rod. The space in between is filled with ammonium chloride, NH4Cl and zinc chloride, ZnCl2. The graphite rod is surrounded by mangan(IV) oxide, MnO2 and carbon.

The voltage of this cell 1.25V to 1.5 V. It does not have a long life because the acidic NH4Cl corrodes the Zinc container. As you know, NH4Cl is a salt that hydrolysed in water, so the pH is less than 7. The hydrogen ions react with zinc to form zinc ions and hydrogen gas. That is why, if you don't use the battery for a certain time, please remove it from your equipment.

ELECTROLYSIS CELL

An electrolysis cell is a process of decomposition of an electrolyte by the passage of electricity through its molten state or aqueous solution.


When an electrolyte is dissolved in water or taken in the molten state it dissociates into positive and negative ions.
LX(l) --> L+(l) + X-(l)
LX(aq) --> L+(aq) + X-(aq)
The positive ions are known as cations and the negative ions are known as anions.

On passing electric current through the electrolyte, cations move towards the cathode and anions move towards the anode.
On reaching their respective electrodes these ions loose their charge. On loosing their charge they get deposited on the electrode or discharged as a gas.
Let us take an example of electrolysis of aqueous copper sulphate solution, CuSO4(aq) using inert electrodes such as platinum electrodes.
In the aqueous solution copper sulphate dissociates into its respective ions.
CuSO4(aq) --> Cu2+(aq) + SO42-(aq)


On passing electric current the copper ions(cations) move towards the cathode and get deposited as copper.
Cu2+(aq) + 2e --> Cu(s)
Simultaneously the sulphate ions(anions) move towards the anode. Because Eo H2O > Eo SO42-, so 2H2O(l) --> O2(g) + 4H+(aq) + 4e
The total ionic equation is :
2Cu2+(aq) + 2H2O(l) --> 2Cu(s) + O2(g) + 4H+(aq)
The molecular equation is :
2CuSO4(aq) + 2H2O(l) --> 2Cu(s) + O2(g) + 2H2SO4(aq)

A VOLTAIC CELL

When you go to the chemistry laboratory and you want to work with electrochemical cells, firstly do the voltaic cell of Zn - Cu.

A voltaic cell is a spontaneous reaction, so that you have to seperate the solution into two half-cells, the first part is oxidation and the other is reduction.


Prepare all the apparatus needed and arrange them as the above picture. For a Zn-Cu cell, please dip a zinc rod in ZnSO4(aq) and a Cu rod in CuSO4(aq). Do not dip Zn rod in CuSO4(aq), because they will react. Connect the Zn rod to the copper rod by using a wire. You can use a galvanometer and a plug key.

The two aqueous solutions in the beackers, ZnSO4 and CuSO4 are interlinked one of another through a salt bridge which is an inverted 'u' tube which is filled with saturated semi solid paste of Agar-agar saturated in NaCl, KCl or KNO3 solution (Agar-agar is a carbohydrate which forms a jelly like substance when dissolved in hot water). You can use filter paper, wet with NaCl(aq). It is more simple than the first.

When the circuit is completed, a deflection is observed in the (G) towards the zinc electrode indicating that the electrons are flowing from the Zn electrode to Cu electrode. The Zn electrode will oxidize.

The electrons lost by the Zn metal and move through electrode and reach the Cu electrode at which they are accepted by Cu2+ ions of the solution to form neutral copper atoms.

In an electrochemical cell, each electrode constitutes one half of the cell and the reaction taking place at the electrode is called half-cell reaction. The overall cell reaction is obtained by adding the two half-cell reactions.

When Zn is added to CuSO4(aq), Zn directly displaces Cu2+(aq) from CuSO4(aq). However, in the electrochemical cell there is no direct contact between Zn and CuSO4(aq). Here, the elecrons can flow from Zn rod to Cu. So the chemical energy changes to the electrical energy. Hence the electrochemical cell acts as a source of electrical current although for a short interval.

The electrode at which oxidation takes place, the metal rod becomes negative charged is called negative electrode. The electrode at which reduction takes place, the metal rod becomes positive charged is called positive electrode.

Accordingly, in the above electrochemical cell, Zn electrode acts as negative electrode while Cu electrode acts as positive.

The function of salt bridge:
a) acts as a link between the two aqueous solution
b) overcomes liquid junction potential.
c) maintains the electrical neutrality of the aqueous solution of the electrodes by releasing or sending oppositely charged ions into the solution.

The cell notation of Zn - Cu is written as : Zn(s)/Zn2+(aq)//C reu2+(aq)/Cu(s) or Zn(s)/ZnSO4(aq)//CuSO4(aq)/Cu(s).

The chemical equation is :
(Anode) Oxidation : Zn(s) --> Zn2+ + 2e Eo = 0,76 volt
(Cathode) Reduction : Cu2+ + 2e --> Cu(s) Eo = 0,34 volt
Redox Reaction : Zn(s)+Cu2+(aq) --> Zn2+(aq)+Cu(s) Eo cell = 1,10 volt

Sometimes you can directly caculate the Eo cell without write down the chemical equation.
Eo cell = Eo Cu2+/Cu - Eo Zn/Zn2+ (Eo of Red at Cathode - Eo of Ox at Anode)
Eo cell = 0,34 volt - . -0,76 volt = 1,10 volt.

THE ANSWER OF ELECTROLYSIS CELL QUIZ Part III

1.An electrolysis of a titanium fluoride complex ion using 1.20 A for 20 min produces 0.179 g of titanium metal. What is the charge of titanium in the material? (Ar: Ti = 48)
Answer (4)
2.It is possible to extract many metals via the electrolysis of aqueous solutions of their ions. Such an experiment is carried out by passing 3.00 Amps, for 2.00 hours, through a solution of metal ions that carry a 2+ charge. 7.11 grams of the metal was produced. Identify the metal.
Answer (Cu)
3.How long would it take in minutes, to produce 5.60 g of Zinc metal from a solution of zinc nitrate using a current of 2.00 Amps?
Answer (138)
4.When molten Copper (II) chloride is electrolyzed by passing 4.00 Amps for 400. seconds what is the maximum mass of copper metal that can be deposited?
Answer (0.526 g)
5.With a current of 20 amps, how long would it take to generate 1.00 kilograms of aluminum by the reaction:Al3+ + 3e- → Al(s)
Answer (5.35 x 105 sec)
6.A mole of electrons has a charge of 96,485 coulombs per mole of electrons. This quantity is known to chemists as ….
Answer (1 faraday)
7.In the electrolytic decomposition of water ….
2H2O → 2H2 + O2
Answer : hydrogen is formed at the cathode and oxygen is formed at the anode
8.Two cells, one containing aqueous AgNO3 and the other containing CuSO4 are set up in series. In a given electrolysis that results in depositing 1.25 g of silver in the first cell, how much copper should deposit simultaneously in the second cell?
Answer (0.368 g)
9.If a constant current of 8.00 amperes is passed through a cell containing Zn2+ for 2.00 hours, how many grams of zinc will plate out onto the cathode?
Answer (19.5 g)
10.In an electrolytic cell, the negative electrode is called the ….
Answer : cathode, at which reduction occurs
11.If the electrolytically driven reaction below, how many grams of material will be produced at the anode by a current of 3.0 A flowing for 1 hour?
Au3+(aq) + Fe(s) <=> Au+(aq) + Fe2+(aq)
Answer (3.13 g)
12.Identify the INCORRECT statement in the following:
Answer : In a voltaic cell a spontaneous reaction is taking place and producing electric current.
13.How many grams of gold could be plated out on the cathode of an electrolytic cell by the passage of 0.5 Amps of current through AuNO3 solution for 30 minutes?
Answer (1.84 g)
14.What is the charge on an ion of tin if 7.42 g of metallic tin is plated out by the passage of 24125 Coulombs through a solution containing the ion?
Answer (+3)

THE ANSWER OF ELECTROLYSIS CELL QUIZ Part II

1.How many minutes will it take an electric current of 3.64 A to deposit all the copper from 740 mL of 0.250 M CuSO4 (aq)? (Ar: Cu = 53.5)
Answer (163)
2.How many hours will it take to plate out all of the Ni in 200 ml of a 0.350 M NiSO4 solution using a current of 0.650 A? (Ar: 59)
Answer (5.77)
3.Calculate the current (mA) required to deposit 0.89 g of tungsten metal in 45 minutes from a solution of WO42-. (Ar: W = 184)
Answer (104)
4.If 130 mg of Cu is plated out from Cu2+ and the process takes 2.0 hours, what was the rate of current (mA)? (Ar: Cu = 53.5)
Answer (55)
5.If 0.123 g of Al is plated out from Al3+ and the process takes 15.0 min, what was the rate of current (A)? (Ar: Al = 27)
Answer (1.47)
6.How many Faradays are required to reduce 0.25 g of Cd2+ to the metal?
(Ar: Cd = 112)
Answer (2.2 x 10-3)
7.How many Faradays are required to reduce 0.40 g of Tl+ to the metal?
(Ar: Tl = 202)
Answer (2.0 x 10-3)
8.How many Faradays are required to reduce 0.10 g of Zr (IV) to the metal? (Ar: Zr = 91)
Answer (7.8 x 10-3)
9.How many Faradays are required to reduce 0.20 g of Eu3+ to the metal?
(Ar: Eu = 152)
Answer (3.9 x 10-3)
10.How many Faradays are required to reduce 0.25 g of Nb (V) to the metal?
(Ar: Nb = 93)
Answer (1.3 x 10-2)
11.A 200.0 mL sample of 0.250 M Cu2+ is electrolyzed for 20.0 minutes with a current of 1.50 A. What is the remaining [Cu2+]? (Ar: Cu = 63.5)
Answer (0.203)
12.A 100.0 dilute solution of Ag+ is electrolyzed for 15.0 minutes with a current of 1.25 mA and the silver is removed completely. What was the initial [Ag+]? (Ar: Ag = 108)
Answer (1.16 x 10-4)
13. If 0.500 L of a 0.600 M SnSO4 solution is electrolyzed for a period of 30.0 min using a current of 4.60 A. If inert electrodes are used, what is the final concentration of Sn2+ remaining in the solution?
Answer (0.514)
14.An aqueous solution of a complex ion of gold is electrolyzed for 54.4 minutes with a current of 30.0 mA to deposit 200 mg of gold. What is the charge of gold in the complex ion? (Ar Au = 197)
Answer (1)

THE ANSWER OF ELECTROLYSIS CELL QUIZ Part I

1.When group I metal salts in solution are electrolyzed, hydrogen gas is produced at the cathode, rather than the free metal. This is because ….
Answer : water is more easily reduced than group I metal ions in solution
2.The correct statement about electrolysis is ….
Answer : the cathode is negative, attract cations and is where reduction takes place
3.In the electrolysis of molten sodium chloride what are the products?
Answer : sodium at the cathode and chlorine at the anode
4.Identify the INCORRECTstatement in the following:
Answer : the cathode is the site of oxidation in an electrochemical cell.
5.How many grams of Ag(s) could be plated out on the cathode of an electrolytic cell by the passage of 20.0 Amps of current through AgNO3 solution for 30 minutes? Faraday's number = 96485 Coul/mol.
Answer (40.3 g)
6.Indium (In) can exist in solution as a couple of different ionic species. Suppose a 2.00 Amp current applied for 500.0 seconds produced 0.397 grams of In(s). What oxidation state is the indium in this solution?
Answer (+3)
7.How many coulombs are provided by a current of 1.00 x 104 A used in the commercial production of sodium in a 8.0 hour period?
Answer (2.9 x 107)
8.How many coulombs are used in the electrodeposition of gold by a current of 30.0 mA for 55 minutes?
Answer (99)
9.How many coulombs are provided by a current of 6.6 x 104 A used in the commercial production of lithium in a 12 hour period?
Answer (2.9 x 1011)
10.Passage of a current for 318 seconds through a silver coulometer results in the deposition of 0.640 g of silver. What is the amperage?
Answer (1.80)
11.Passage of a current for 437 seconds through a silver coulometer results in the deposition of 0.742 g of silver. What is the amperage?
Answer (1.52)
12.Passage of a current for 348 seconds through a silver coulometer results in the deposition of 0.498 g of silver. What is the amperage?
Answer (1.28)
13.An acidic solution containing the BiO+ ion is electrolyzed using a current of 0.750 A. How many grams of Bi plate out in 30.0 min? (Ar: Bi = 209)
Answer (0.97)
14.Beryllium occurs naturally in the form of beryl. The metal is produced from its ore by electrolysis after the ore has been converted to the oxide and then to the chloride. How many grams of Be(s) is deposited from a BeCl2 solution by a current of 5.0 A that flows for 1.0 h? (Ar: Be = 9)
Answer (0.84)
15.A proposed battery involves the reaction of Zn(s) and Cl2 (g) to give ZnCl2. If the battery is to deliver 1.5 A for 25 hours, what mass (g) of zinc must the anode contain? (Ar: Zn = 65.4)
Answer (460)
16.Electrolysis can be used to determine atomic masses. A current of 0.450 A deposits 0.786 g of a certain metal in 50.0 minutes. Calculate the atomic mass of the metal if n = 2.
Answer (112)
17.Electrolysis can be used to determine atomic masses. A current of 0.550 A deposits 0.358 g of a certain metal in 45.0 minutes. Calculate the atomic mass of the metal if n = 3.
Answer (70)
18.Electrolysis can be used to determine atomic masses. A current of 0.600 A deposits 2.38 g of a certain metal in exactly 1.00 hour. Calculate the atomic mass of the metal if n = 1.
Answer (106)
19.How many minutes will it take to plate out 5.00 g of Fe from an Fe(NO3)3 solution by a current of 1.50 A? (Ar: Fe = 56)
Answer (288)

THE ANSWER OF VOLTAIC CELL QUIZ Part II

1.The equation that represents a reaction that is not a redox reaction is ….
1. Zn + CuSO4 → ZnSO4 + Cu
2. 2H2O2 → 2H2O + O2
3. H2O + CO2 → H2CO3
4. 2H2 + O2 → 2H2O
Answer (Reaction no. 3)
2.For the galvanic cell described below, the correct line notation is ….
Cl2 + 2e- → 2Cl- (E0 = 1.36v)
Cu+ + e- → Cu (E0 = 0.52v)
Answer : Pt(s)Cu(s)Cu+(aq)Cl2(g)2Cl-(aq)Pt(s)
3.What is indicated when a chemical cell's voltage (E) has dropped to zero?
Answer : The cell reaction has reached equilibrium.
4.Given the redox reaction:
2 Cr(s) + 3 Cu2+(aq) --> 2 Cr3+(aq) + 3 Cu(s)
Which reaction occurs at the cathode in an electrochemical cell?
Answer : reduction of Cu2+(aq)
5.Given the cell reaction:
2 H2O(l) --> 2 H2(g) + O2(g)
The cell is best described as ....
Answer : an electrolytic cell in which an endothermic reaction occurs
6.In an electrochemical cell, what is the purpose of the salt bridge?
Answer : It permits the migration of ions between the half-cells.
7.In a voltaic cell what type of ions move toward the cathode?
Answer : anions
8.What is the equation for the net cell reaction for the electrochemical cell:
Pb(s) PbI2(s) HI(aq) H2(g) Pt(s)
Answer : Pb(s) + 2HI(aq) --> PbI2(s) + H2
9.Referring to the table of Standard Cell Potentials below, determine the standard cell potential for the following reaction running in this direction:
2 Fe3+(aq) + Zn(s) --> 2 Fe2+(s) + Zn2+(aq)
Answer (+1.53 V)

STANDARD REDUCTION POTENTIALS E°(volts)
F2 + 2 e- ---> 2 F- Eo = +2.87 V
Au+ + e- ---> Au Eo = +1.69 V
Ag+ + e- ---> Ag Eo = +0.80 V
Fe3+ + e- ---> Fe2+ Eo = +0.77 V
Cu2+ + 2 e- ---> Cu Eo = +0.34 V
2 H+ + 2 e- ---> H2 Eo = 0 V
Pb2+ + 2 e- ---> Pb Eo = -0.13 V
Fe2+ + 2 e- ---> Fe Eo = -0.44 V
Zn2+ + 2 e- ---> Zn Eo = -0.76 V
Na+ + e- ---> Na Eo = -2.71 V
Li+ + e- ---> Li Eo = -3.05 V
10.Which of the following metal ions in aqueous solution is most easily oxidized to its aqueous ionic form?
Answer (Na)
11.Which metal is used as a coating on steel to limit corrosion?
Answer (Zn)
12.Given the nickel-cadmium battery reaction:
2 NiOOH + Cd + 2 H2O --> 2 Ni(OH)2 + Cd(OH)2
What occurs during discharge in the nickel-cadmium battery?
Answer : Ni3+ is reduced to Ni2+.
13.Referring to the table of standard cell potentials attached, determine the standard cell potential of the following reaction for the corrosion of iron in an acidic environment:
Fe(s) + 2 H+(aq) +1/2 O2(g) --> Fe2+(aq) + H2O(l)
Answer (Eo = +0.44 V)
14.Which ion in solution is most easily reduced to its elemental form?
Cu2+
15.In the alkaline energy cell the overall reaction is: Zn(s) + 2MnO2(s) + 2H2O ---> Zn(OH)2(s) + 2MnO(OH)(s). Which of the following half-reactions is taking place at the cathode?
2MnO2(s) +2 H2O + 2e- ---> 2MnO(OH)(s) + 2OH-(aq)
16.In the lead storage battery the product of both the cathode and anode reactions is?
Answer (PbSO4)
17.The fuel cell we discussed in class forms the following product:
Answer (H2O)
18.In an alkaline energy cell the overall cell reaction is as follows:
Zn(s) + 2 MnO2(s) + 2 H2O --> Zn(OH)2(s) + 2 MnO(OH)
Which of the following reactions is taking place at the cathode?
Answer : Zn(OH)2(s) + 2e- --> Zn(s) + 2 OH-(aq)
19.In a Nickel-Cadmium cell the following overall reaction is taking place:
Cd(s) + NiO2(s) + 2 H2O --> Cd(OH)2(s) + Ni(OH)3(s)
Which of the following half-reactions are taking place at the anode?
Answer : Cd(s) + 2 OH-(aq) --> Cd(OH)2(s) + 2e-

THE ANSWER OF VOLTAIC CELL QUIZ Part I

1.If the two half-cells below were combined, what would be the correct chemical equation to represent the spontaneous REDOX process?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
Answer : Cu2+ + H2 ==> 2H+ + Cu
2.If the two half-cells below were combined, what would be the voltage generated by the spontaneous REDOX process?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
Answer (+0.34V)
3.If the two half-cells below were combined, which cell would undergo reduction?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
Answer : Copper half-cell
4.If the two half-cells below were combined, what would be the expected products of the spontaneous chemical reaction?
Zn2+ + 2e- <====> Zn (-0.76V)
H+ + e- <====> 1/2 H2 (0.00V)
Answer : H2 and Zn2+
5.Which of the following statements is FALSE?
Answer : Metal can be used for salt bridge
6.The following REDOX reactions all have positive Ecell voltages.
Cl2 + 2Br- ==> Br2 + 2Cl-
Br2 + 2I- ==> I2 + 2Br-
Cl2 + 2I- ==> I2 + 2Cl-
Which is the correct order of strength of oxidizing agent, from weakest to strongest?
Answer : Iodine < Bromine < Chlorine
7.The standard reduction potential for Zn2+ + 2e- ==> Zn, is -0.76 V, and the standard reduction potential for Fe3+ + e- ==> Fe2+, is +0.77V. What is the Ecell for the reaction below?
2Fe3+ + Zn ==> Zn2+ + 2Fe2+
Answer (+1.53)
8.Iron rusts when it comes into contact with water and oxygen. The change that the iron undergoes can be summarized thus; Fe ==> Fe2+ + 2e-. When iron metal is coated with solid zinc in a process called galvanizing, the oxidation of iron is prevented even if the zinc coating does not completely cover the iron metal. Which of the following statements serves best to explain these observations?
Answer : Solid zinc metal is more easily oxidized than iron
9.In the spontaneous reduction of Copper (II) ions with Nickel metal to form Copper metal and Nickel (II) ions, what will happen to the Ecell value when the concentration of Copper (II) ions is increased?
Cu2+ + 2e- <====> Cu (+0.34V)
Ni2+ + 2e- <====> Ni (-0.25V)
Answer : Ecell will increase
10.If the two half-cells below were combined, into which cell do anions from the salt bridge flow?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
Answer : Hydrogen
11.What value of Ecell do you expect for Pb(s) → Pb2+ + 2e-
in 0.015 M Pb2+ solution? E0 = +0.13 V
Answer (E = 0.00V)
12.Reduction potential is ....
Answer : an intensive property
13.The standard hydrogen electrode is assigned a potential of ….
Answer : zero volts
14.Calculate the value of E0cell for a galvanic cell that contains the following half cells:
Cl2 + 2e- → 2Cl- (E0 = 1.36v)
Cu+ + e- → Cu (E0 = 0.52v)
Answer (E0cell = 0.84 volts)
15.In all electrochemical cells, the process that takes place at the anode is … and the process that takes place at the cathode is ….
Answer : oxidation, reduction

STOICHIOMETRY QUIZ Part II

1.If 100 cm3 of a hydrogen gas is added to 200 cm3 of a chlorine gas, forms hydrogen chloride gas (P,T). The volume of the product is ….
a.100 cm3
b.200 cm3
c.300 cm3
d.400 cm3
e.500 cm3
2.Two dm3 of CxHy gas burns in 5 dm3 oxygen gas. If there is 4 dm3 CO2(g), the chemical formula of CxHy is ….
a.C2H2
b.C2H4
c.C2H6
d.C3H3
e.C3H6
3.One dm3 of CxHy gas burns in 2 dm3 of an oxygen gas. If there is 1 dm3 of CO2(g), the chemical formula of CxHy is ….
a.CH4
b.C2H2
c.C2H4
d.C3H3
e.C3H6
4.Ethane gas, C2H6 is burned in air. The volume of ethane gas is 4,0 dm3. The volume of oxygen gas at the same P and T which needed in the burning is ….
a.3,5 dm3
b.7,0 dm3
c.10,5 dm3
d.14,0 dm3
e.28,0 dm3
5. Eight litters of hydrogen gas combines with x litters of chlorine gas to form eight litters of hydrogen chloride gas. The value of x is ….
a.2
b.4
c.6
d.8
e.10
6.Silver (Atomic mass 107.87) has two naturally-occurring isotopes with isotopic mass of 106.91 and 108.90. What is the percentage abundance of the heavier isotope?
a.47.24
b.51.82
c.48.16
d.49.05
e.50.95
7.The formula mass relative of copper(II) sulfate pentahydrate is …. (Ar Cu = 63,5; S = 32; O = 16; and H = 1)
a.159,5
b.249,5
c.255,5
d.313,0
e.403,0
8.The formula mass relative of barium hydroxide octahydrate is …. (Ar Ba = a; Ar O = b; and Ar H = c)
a.8 (a + 3b+ 4c)
b.(a + 2b + 2c) (16c + 8b)
c.(a + 2b + 2c) 8 (2c + b)
d.(a + 2b + 2c) + 8 (b + 2c)
e.(a + 2b + 2c) (2c + b)
9.Which of the following organic compounds has the lowest molecular mass? (ArC = 12, N = 14, H = 1).
a.C7H14
b.C6H10N2
c.C4H8N4
d.C7H11N
e.C5H11N3

STOICHIOMETRY QUIZ Part I

1.According to the Lavoisier’s Law, if a 12 grams of Mg(s) reacts with a 10 g of oxygen(g), the product formed is 20 g MgO(s) and there is an excess of oxygen gas. The wrong answer is ….
a.after reaction the mass = 22 grams
b.not all of the oxygen gas reacts with Mg
c.the excess mass of oxygen gas is 2 grams
d.the mass of product = the mass of reactants
e.all magnesium reacts to form magnesium oxide
2.Sodium(s) reacts with an oxygen gas in the air, forms an oxide. If the mass of sodium is 2,3 g and the mass of the oxide is 3,1 g, the mass of oxygen gas is ….
a.less than 0,8 g
b.0,8 g
c.more than 0,8 g
d.1,6 g
e.more than 1,6 g
3.Potassium(s) reacts with an oxygen gas in the air, forms a metal oxide(s). If the mass of potassium is 3,9 g and the mass of the oxide is 4,7 g, the correct answer is ….
a.m O2(g) = 0,8 g
b.m K2O(s) < m K(s)
c.m K(s) = m K2O(s)
d.the mass of reactants > 4,7 g
e.the mass of product < the mass of reactants
4.If a 6,5 grams of Zn(s) reacts with a 2 grams of O2(g), the compound formed is 8,1 grams ZnO(s) and there is an excess of oxygen gas. The wrong answer is
a.the limiting reactant is zinc
b.all zinc reacts to form zinc oxide
c.after reaction the mass = 8,1 grams
d.not all of the oxygen gas reacts with zinc
e.the excess mass of oxygen gas is 0,4 grams
5.Cu(s) + S(s)  CuS(s) The correct answer which relates with the graph is ..
a.the mass ratio of Cu : S = 1 : 2
b.the mass of Cu = the mass of S
c.if m Cu = 10 g, m S = 20 g
d.the mass’ ratio of both elements can change
e.if m S = 6 g, m Cu = 12 g
6.Cu(s) + S(s)  CuS(s) The mass’ ratio of Cu : S in CuS = 2 : 1. The wrong answer about this information is ….
a.if the mass of Cu = 4 g, the mass of S = 2 g
b.if m S = 20 g, m CuS = 60 g
c.the mass’ ratio of both elements can change
d.this reaction proves the Proust’s Law
e.the mass before and after reaction are the same
7.Carbon and oxygen can form two different compounds, CO and CO2. The mass of CO = 2,8 g and the mass of CO2 = 4,4 g. If the mass of C in both compounds is 1,2 g, the wrong answer is ….
a.m O in CO > m O in CO2
b.m O in CO : O in CO2 = 1 : 2
c.if m C = 2,4 g; m O in CO = 3,2 g
d.the mass of O in first compound is 1,6 g
e.the mass of O in the second compound is 3,2 g
8.There are two compounds, NO and NO2. The mass of NO=30g and the mass of NO2=46g. If the mass of N in both compounds is 14 g, the wrong answer is ….
a.the mass of O in first compound is 16 g
b.the mass of O in the second compound is 32 g
c.the mass’ ratio of O in NO : O in NO2 = 2 : 1
d.if the mass of N = 7 g, m O in NO = 8 g
e.if the mass of N = 28 g, m O in NO : O in NO2 = 1 : 2
9.In an industrial process, hydrogen chloride, HCl is prepared by burning hydrogen gas in atmosphere of chlorine. If a 10 dm3 of HCl(g) is produced, the total volume of H2(g) and Cl2(g) are ….
a.5 dm3
b.10 dm3
c.20 dm3
d.30 dm3
e.40 dm3
10.If 150 cm3 of a hydrogen gas, H2 is added to 200 cm3 of a nitrogen gas, N2 forms ammonia gas,NH3 (P,T). The volume of ammonia is ….
a.50 cm3
b.100 cm3
c.150 cm3
d.200 cm3
e.250 cm3

CHEMICAL EQUATION QUIZ Part II

1.Solid calcium carbonate is added to a solution of nitric acid to form carbon dioxide gas. The correct balanced equation is ….
a.CaCO3(s) + HNO2(aq) --> Ca(NO3)2(aq) + H2O(l) + CO2(g)
b.CaCO3(s) + 2HNO2(aq) --> Ca(NO3)2(aq) + H2O(l) + CO2(g)
c.CaCO3(s) + HNO3(aq) --> Ca(NO3)2(aq) + H2O(l) + CO2(g)
d.CaCO3(s) + 2HNO3(aq) --> Ca(NO3)2(aq) + H2(l) + CO2(g)
e.CaCO3(s) + 2HNO3(aq) --> Ca(NO3)2(aq) + H2O(l) + CO2(g)
2.Aluminium is added to a solution of hydrochloric acid to form a solution of alminium chloride and hydrogen gas. The correct balanced equation is ….
a.Al(s) + HCl(aq) --> AlCl(aq) + H(g)
b.Al(s)+2HCl(aq)--> AlCl2(aq)+H2(g)
c.2Al(s)+6HCl(aq)--> 2AlCl3(aq)+ 3H2(g)V
d.Al2(s)+6HCl(aq)--> 2AlCl3(aq) + 3H2(g)
e.2Al(s) + 6HCl(aq) --> 2AlCl3(aq) + 6H(g)
3.If an acid is added to a base and the reaction is heated, the compound formed is called ….
a.non-acid
b.non-base
c.salt
d.water
e.ionic compound
4.Iron is added to hydrochloric acid, form salt and a gas. The gas is ….
a.Oxygen
b.hydrogen
c.iron
d.chlorine
e. hydrogen chloride
5.Propane gas, C3H8 burns fully in oxygen gas. The ratio of molecules of propane, oxygen, carbon dioxide, and water are
a.1, 5, 3, 4
b.1, 4, 3, 5
c.1, 3, 4, 5
d.2, 3, 3, 5
e.2, 5, 6, 8
6.Butane gas, C4H10 is also burnt as a source of energy. One molecule of butane gas reacts with oxygen gas to form carbon dioxide gas and water. The correct number of carbon dioxide molecules and water molecules are ….
a.2 and 3
b.2 and 5
c.4 and 3
d.4 and 5
e.4 and 10
7.Pentane liquid, C5H12 burns fully in oxygen gas. The ratio of molecules of pentane, oxygen, carbon dioxide, and water are ….
a.1, 11, 5, 6
b.1, 8, 5, 6
c.1, 5, 3, 4
d.2, 5, 3, 5
e.2, 10, 6, 8
8.Fossil fuels usually contain traces of sulfur. The poisonous gas formed when this fuel burns is ….
a.acid
b.sulfur
c.sulfur dioxide
d.sulfur trioxide
e.sulfurous acid
9.Propane, like methane, is a hydrocarbon which can be used as a fuel. It is sold as ‘bottled gas’, for use where there is no mains gas supply. When propane burns with sufficient oxygen, the products formed are ….
a.oxygen and water
b.oxygen and carbon dioxide
c.water and carbon dioxide
d.carbon dioxide and carbon monoxide
e.carbon monoxide and water

CHEMICAL EQUATION QUIZ Part I

1.Heated calcium burns in chlorine to form salt. The correct word equation is ….
a.calcium + chlorine --> calcium chlorine
b.calcium + chlorine --> calcium chloride
c.calcium(s) + chlorine(g) --> calcium chlorine(s)
d.calcium(s) + chlorine(g) --> calcium chloride(g)
e.calcium(s) + chlorine(g) --> calcium chloride(s)
2.Aluminium (group IIIA) reacts rapidly with fluorine (group VIIA) to form aluminium fluoride. The correct formula of the product is ….
a.AlF(s)
b.AlF2(s)
c.AlF3(s)
d.Al3F(s)
e.Al2F(s)
3.Balance the following equation. What is the sum of the coefficients of the reactants and products?
C3H8O2 + O2 --> CO2 + H2O
a.17
b.15
c.12
d.10
e.9
4.Balance the following equation. What is the sum of the coefficients of the reactants?
C6H8O6 + 2 --> CO2 + H2O
a.16
b.15
c.10
d.6
e.5
5.Balance the following equation. What is the sum of the coefficients of the reactants?
C12H22O11 + O2 --> CO2 + H2O
a.7
b.9
c.10
d.12
e.13
6.Balance the following equation. What is the sum of the coefficients of the products?
C + HNO3 --> NO2 + H2O + CO2
a.4
b.5
c.6
d.7
e.9
7.Balance the following equation and choose the quantity which is the sum of the coefficients of the reactants and products.
P2H4 --> PH3 + P4
a.9
b.12
c.14
d.15
e.16
8.Balance the following equation and choose the quantity which is the sum of the coefficients of the reactants and products.
CuSO4 + KI --> CuI + I2 + K2SO4
a.13
b.12
c.11
d.10
e.9
9.Balance the following equation and choose the quantity which is the sum of the coefficients of the products.
SnS2 + HCl --> H2SnCl6 + H2S
a.8
b.7
c.6
d.5
e.3
10.Balance the following equation and choose the quantity which is the sum of the coefficients of the products.
CS2 + Cl2 --> CCl4 + S2Cl2
a.6
b.5
c.4
d.3
e.2
11.Balance the following equation and choose the quantity which is the sum of the coefficients of the reactants and products.
I2 + Na2S2O3 --> Na2S4O6 + NaI
a.8
b.4
c.6
d.5
e.9
12.Potassium, with atomic number 19, reacts rapidly with fluorine to form potassium fluoride. The correct answer of the balanced equation is ….
a.K(s) + 3F(g) --> KF3(s)
b.K(s) + F2(g) --> KF2(s)
c.2K(s) + F2(g) --> 2KF(s)
d.K(s) + F(g) --> KF(s)
e.K2(s) + F2(g) --> 2KF(s)
13.The correct answer about the balanced chemical equation of forming aluminium oxide is ….
a.2Al(s) + O(g) --> Al2O(s)
b.Al(s) + O(g) --> AlO(s)
c.2Al(s) + O2(g) --> 2AlO(s)
d.4Al(s) + 3O2(g) --> 2Al2O3(s)
e.2Al2(s) + 3O2(g) --> 2Al2O3(s)
14.One of the following equations is incorrectly balanced. The equation is ….
a.N2(g) + 3H2(g) --> 2NH3(g)
b.2Fe(s) + 3O2(g) --> 2Fe2O3(s)
c.Ca(s)+2HCl(aq)-->CaCl2(aq)+H2(g)
d.3Mg(s) + N2(g) --> Mg3N2(s)
e.2H2(g) + O2(g) --> 2H2O(l)
15.Methane gas is burnt as a source of energy for cooking and heating. One molecule of methane gas and 2 molecules of oxygen gas react to form 1 molecule of carbon dioxide gas and 2 molecules of water. The correct equation is ….
a.CH4 + O2 --> CO2 + H2O
b.CH4 + 2O2 --> CO2 + 2H2O
c.CH4(g) + O2(g) --> CO2(g) + H2O(g)
d.CH4(g) + 2O2(g) --> CO2(g) + 2H2O(g)
e.CH4(g) + 2O2(g) --> CO2(g) + 2H2O(l)

CHEMISTRY NOMENCLATURE QUIZ Part II

1.What is the chemical name of MnCl2?
a.Manganese perchlorite
b.Manganese chlorite
c.Manganese chlorate
d.Manganese chloride
e.Manganese(II) chloride
2.What is the chemical names of Fe3 (PO4)2?
a.Iron (II) phosphide
b.Iron (III) phosphite
c.Iron (II) phosphite
d.Iron (III) phosphate
e.Iron (II) phosphate
3.What is the chemical name of BaS?
a.Barium sulfite
b.Barium sulfoxide
c.Barium sulfate
d.Barium sulfur
e.Barium sulfide
4.What is the chemical name of Mg3N2?
a.Magnesium nitride
b.Magnesium nitrate
c.Magnesium nitrite
d.Magnesium nitrade
5.Magnesium from group IIA in the periodic table, burns brightly in air to form oxide. The formula and name of this oxide are ….
a.Mg3O, magnesium(III) oxide
b.Mg2O, dimagnesium oxide
c.MgO, magnesium oxide
d.MgO2, magnesium dioxide
e.MgO3, magnesium oxide
6.The correct name of the following ionic compounds is ….
a.K+ and CO32- : sodium carbide
b.Ca2+ and NO3- : potassium nitride
c.Ba2+ and SO42 - : barium sulfate
d.Al3+ and CO32 - : aluminium carbide
e.Mg2+ and PO33- : magnesium fosfide
7.The correct statement about acid and base is ….
a.an acid is a cation
b.a base is an anion
c.an acid is an ionic compound
d.a base is a covalent compound
e.an acid produces hydrogen ion when dissolved in water
8.The formula of hydrochloric acid is ....
a.HCl
b.HOCl
c.ClO
d.ClO2
d.HClO2
9.The correct formula of base is ....
a.SOH
b.BrOH
c.Ca(OH)2
d.CH3OH
e.CH3COOH
10.If an acid releases a hydrogen ion, the result of the other ion is ....
a.cation
b.hydroxide
c.anion
d.negative ion
e.positive ion

CHEMISTRY NOMENCLATURE QUIZ Part I

1.Loss of an electron by a neutral atom results in the formation of ….
a.a cation
b.an isotope
c.an anion
d.a polyatomic ion
e.a nucleus
2.A cation has a positive charge because ….
a.there are fewer electrons than protons
b.there are more electrons than protons
c.the neutrons in the nucleus are charged
d.there are fewer neutrons than protons
e.it has a positively charged nucleus
3.Gain of an electron by a neutral atom results in the formation of ….
a.an anion
b.a cation
c.an isotope
d.a nucleus
e.a polyatomic ion
4.What is the symbol for the phosphate ion?
a.PO4-
b.PO34-
c.PO43-
d.PO-
e.PO33-
5.What is the symbol for the chlorate ion?
a.ClO42-
b.ClO2-
c.ClO3-
d.ClO4-
e.ClO32-
6.What is the symbol for the nitrate ion?
a.NO2-
b.NO32-
c.NO3-
d.NO-
e.NO23-
7.What is the symbol for the bisulfate ion?
a.HSO42-
b.H2SO4-
c.HSO32-
d.HSO3-
e.HSO4-
8.What is the symbol for the perchlorate ion?
a.ClO23-
b.CrO4-
c.ClO-
d.ClO3-
e.ClO4-
9.What is the symbol for the carbonate ion?
a.CO3-
b.CO-
c.CO22-
d.CO2-
e.CO32-
10.The correct formula of non-metal oxide is ….
a.Na2O
b.Li2O
c.BaO
d.SO2
e.SrO
11.Metal M, with atomic number 20, has an oxide with formula ….
a.M3O2
b.M2O
c.MO
d.MO3
e.M2O3
12.The correct formula for the ionic compound which is formed from K+ and S2- is ….
a.KS
b.K2S
c.KS2
d.SK
e.SK2
13.What is the chemical formula for gold (III) oxide?
a.Au2O3
b.Au3O
c.AuO3
d.Au3O2
e.AuO
14.What is the chemical formula of tin (IV) oxide?
a.SnO4
b.Sn4O
c.SnO2
d.Sn(OH)4
e.Sn(OH)2
15.The formula of rust is Fe2O3. The correct name of rust is ….
a.iron oxide
b.iron trioxide
c.diiron trioxide
d.iron(II) oxide
e.iron(III) oxide

ELECTROLYSIS CELL QUIZ Part III

1.An electrolysis of a titanium fluoride complex ion using 1.20 A for 20 min produces 0.179 g of titanium metal. What is the charge of titanium in the material? (Ar: Ti = 48)
a)6
b)4
c)3
d)2
e)1
2.It is possible to extract many metals via the electrolysis of aqueous solutions of their ions. Such an experiment is carried out by passing 3.00 Amps, for 2.00 hours, through a solution of metal ions that carry a 2+ charge. 7.11 grams of the metal was produced. Identify the metal.
a) Ba
b) Cu
c) Ni
d) Sr
e) Zn
3.How long would it take in minutes, to produce 5.60 g of Zinc metal from a solution of zinc nitrate using a current of 2.00 Amps?
a) 138
b) 826
c) 65.4
d) 6.54
e) 2.00
4.When molten Copper (II) chloride is electrolyzed by passing 4.00 Amps for 400. seconds what is the maximum mass of copper metal that can be deposited?
a) 0.526 g
b) 63.5 g
c) 6.35 g
d) 1600 g
e) 96500 g
5.With a current of 20 amps, how long would it take to generate 1.00 kilograms of aluminum by the reaction:
Al3+ + 3e- → Al(s)
a)2.19 x 104 sec
b)1.68 x 102 sec
c)1.78 x 105 sec
d)5.35 x 105 sec
e)3.90 x 103 sec
6.This picture of an electrochemical cell can best be described as:
a)a complete galvanic cell
b)a complete electrolytic cell
c)an electrolytic cell, but missing at least one essential component
d)a galvanic cell, but missing at least one essential component
7.A mole of electrons has a charge of 96,485 coulombs per mole of electrons. This quantity is known to chemists as ….
a)1 joule
b)1 watt
c)1 ampere
d)1 volt
e)1 faraday
8.In the electrolytic decomposition of water ….
2H2O → 2H2 + O2
a)hydrogen is formed at both the anode and the cathode
b)hydrogen is formed at the cathode and oxygen is formed at the anode
c)hydrogen is formed at the anode and oxygen is formed at the cathode
9.oxygen is formed at both the anode and the cathode
Two cells, one containing aqueous AgNO3 and the other containing CuSO4 are set up in series. In a given electrolysis that results in depositing 1.25 g of silver in the first cell, how much copper should deposit simultaneously in the second cell?
a)1.25 g
b)1.47 g
c)0.736 g
d)0.368 g
e)2.65 g
10.If a constant current of 8.00 amperes is passed through a cell containing Zn2+ for 2.00 hours, how many grams of zinc will plate out onto the cathode?
a)19.5 g
b)39.0 g
c)1.43 x 103 g
d)126 g
e)0.985 g
11.In an electrolytic cell, the negative electrode is called the ….
a) anode, at which oxidation occurs
b) anode, at which reduction occurs
c) cathode, at which oxidation occurs
d) cathode, at which reduction occurs
12.If the electrolytically driven reaction below, how many grams of material will be produced at the anode by a current of 3.0 A flowing for 1 hour?
Au3+(aq) + Fe(s) <=> Au+(aq) + Fe2+(aq)
a) 5.5 g
b) 22.0 g
c) 3.13 g
d) 6.26 g
e) 11.0 g
13.Identify the INCORRECT statement in the following:
a) In a voltaic cell a spontaneous reaction is taking place and producing electric current.
b) The gain of electrons takes place at the cathode.
c) Measuring the potential of a cell provides a direct determination of the free energy of the cell reaction.
d) Sodium metal and chlorine gas are produced in an electrolytic cell containing aqueous NaCl.
e) Faraday¹s number is the amount of charge in Coulombs of one mole of electrons.
14.How many grams of gold could be plated out on the cathode of an electrolytic cell by the passage of 0.5 Amps of current through AuNO3 solution for 30 minutes?
a) 3.07 x 10-2 g
b) 2.41 g
c) 1.84 g
d) 3.68 g
e) 17.9 g
15.What is the charge on an ion of tin if 7.42 g of metallic tin is plated out by the passage of 24125 Coulombs through a solution containing the ion?
a) +4
b) +3
c) +2
d) +1
e) 0

ELECTROLYSIS CELL QUIZ Part II

1.How many minutes will it take an electric current of 3.64 A to deposit all the copper from 740 mL of 0.250 M CuSO4 (aq)? (Ar: Cu = 53.5)
a)102
b)144
c)163
d)208
e)182
2.How many hours will it take to plate out all of the Ni in 200 ml of a 0.350 M NiSO4 solution using a current of 0.650 A? (Ar: 59)
a)5.16
b)4.26
c)5.77
d)2.88
e)3.42
3.Calculate the current (mA) required to deposit 0.89 g of tungsten metal in 45 minutes from a solution of WO42-. (Ar: W = 184)
a)265
b)173
c)421
d)132
e)104
4.If 130 mg of Cu is plated out from Cu2+ and the process takes 2.0 hours, what was the rate of current (mA)? (Ar: Cu = 53.5)
a)28
b)42
c)64
d)35
e)55
5.If 0.123 g of Al is plated out from Al3+ and the process takes 15.0 min, what was the rate of current (A)? (Ar: Al = 27)
a)0.490
b)1.21
c)1.64
d)0.812
e)1.47
6.How many Faradays are required to reduce 0.25 g of Cd2+ to the metal?
(Ar: Cd = 112)
a)4.4 x 10-3
b)7.8 x 10-3
c)4.3 x 10-4
d)1.3 x 10-3
e)2.2 x 10-3
7.How many Faradays are required to reduce 0.40 g of Tl+ to the metal?
(Ar: Tl = 202)
a)4.0 x 10-3
b)1.0 x 10-4
c)1.0 x 10-3
d)4.0 x 10-4
e)2.0 x 10-3
8.How many Faradays are required to reduce 0.10 g of Zr (IV) to the metal? (Ar: Zr = 91)
a)3.9 x 10-3
b)8.6 x 10-4
c)7.8 x 10-3
d)4.4 x 10-3
e)1.1 x 10-3
9.How many Faradays are required to reduce 0.20 g of Eu3+ to the metal?
(Ar: Eu = 152)
a)1.3 x 10-3
b)3.9 x 10-3
c)8.6 x 10-4
d)4.3 x 10-4
e)7.8 x 10-3
10.How many Faradays are required to reduce 0.25 g of Nb (V) to the metal?
(Ar: Nb = 93)
a)7.8 x 10-3
b)1.3 x 10-2
c)1.3 x 10-3
d)2.7 x 10-3
e)2.7 x 10-2
11.A 200.0 mL sample of 0.250 M Cu2+ is electrolyzed for 20.0 minutes with a current of 1.50 A. What is the remaining [Cu2+]? (Ar: Cu = 63.5)
a)0.156
b)0.221
c)0.203
d)0.171
e)0.185
12.A 100.0 dilute solution of Ag+ is electrolyzed for 15.0 minutes with a current of 1.25 mA and the silver is removed completely. What was the initial [Ag+]? (Ar: Ag = 108)
a)2.32 x 10-1
b)2.32 x 10-4
c)1.16 x 10-4
d)2.32 x 10-3
e)1.16 x 10-1
13.If 0.500 L of a 0.600 M SnSO4 solution is electrolyzed for a period of 30.0 min using a current of 4.60 A. If inert electrodes are used, what is the final concentration of Sn2+ remaining in the solution?
a)0.342
b)0.544
c)0.514
d)0.389
e)0.430
14.An aqueous solution of a complex ion of gold is electrolyzed for 54.4 minutes with a current of 30.0 mA to deposit 200 mg of gold. What is the charge of gold in the complex ion? (Ar: = 197)
a)1
b)2
c)3
d)4
e)5

ELECTROLYSIS CELL QUIZ Part I

1.When group I metal salts in solution are electrolyzed, hydrogen gas is produced at the cathode, rather than the free metal. This is because ….
a.aqueous solutions of group I metals do not conduct electricity
b.water is more easily reduced than group I metal ions in solution
c.the voltage required for the reaction is too high
d.group I metal salts are insoluble
e.group I metal is unreactive
2.The correct statement about electrolysis is ….
a.the anode is positive, attracts anions and is where reduction takes place
b.the anode is negative, attracts cations and is where reduction takes place
c.the cathode is negative, attracts anions and is where oxidation takes place
d.the cathode is negative, attract cations and is where oxidation takes place
e.the cathode is negative, attract cations and is where reduction takes place
3.In the electrolysis of molten sodium chloride what are the products?
a.sodium at the cathode and chlorine at the anode
b.chlorine at the cathode and sodium at the anode
c.hydrogen at the anode and chlorine at the cathode
d.hydrogen at the cathode and chlorine at the anode
e.chlorine at the cathode and oxygen at the anode
4.Identify the INCORRECTstatement in the following:
a.sodium metal and chlorine gas are produced in an electrolytic cell containing molten NaCl.
b.the cathode is the site of oxidation in an electrochemical cell.
c.a negative cell potential means that the free energy of the reaction in the cell is positive.
d.one Faraday of charge will reduce 1/2 mole of Cu+2 ions to Cu(s).
e.in a voltaic cell a spontaneous reaction is occurring producing electric current.
5.How many grams of Ag(s) could be plated out on the cathode of an electrolytic cell by the passage of 20.0 Amps of current through AgNO3 solution for 30 minutes? Faraday's number = 96485 Coul/mol.
a.40.3 g
b.4,03 g
c.0.671 g
d.0.373 g
e.6.2 x 10-3 g
6.Indium (In) can exist in solution as a couple of different ionic species. Suppose a 2.00 Amp current applied for 500.0 seconds produced 0.397 grams of In(s). What oxidation state is the indium in this solution?
a.+4
b.+3
c.+2
d.+1
e.0
7.How many coulombs are provided by a current of 1.00 x 104 A used in the commercial production of sodium in a 8.0 hour period?
a.4.8 x 105
b.3.6 x 106
c.4.8 x 107
d.3.6 x 107
e.2.9 x 107
8.How many coulombs are used in the electrodeposition of gold by a current of 30.0 mA for 55 minutes?
a.99
b.1.8
c.1.6
d.1.8 x 103
e.9.9 x 104
9.How many coulombs are provided by a current of 6.6 x 104 A used in the commercial production of lithium in a 12 hour period?
a.4.8 x 109
b.2.9 x 109
c.2.4 x 1010
d.4.8 x 1011
e.2.9 x 1011
10.Passage of a current for 318 seconds through a silver coulometer results in the deposition of 0.640 g of silver. What is the amperage?
a.1.98
b.1.85
c.1.80
d.1.71
e.1.65
11.Passage of a current for 437 seconds through a silver coulometer results in the deposition of 0.742 g of silver. What is the amperage?
a.1.52
b.1.43
c.1.38
d.1.30
e.1.24
12.Passage of a current for 348 seconds through a silver coulometer results in the deposition of 0.498 g of silver. What is the amperage?
a.1.45
b.1.37
c.1.32
d.1.28
e.1.20
13.An acidic solution containing the BiO+ ion is electrolyzed using a current of 0.750 A. How many grams of Bi plate out in 30.0 min? (Atomic weight: Bi = 209)
a.1.99
b.0.97
c.1.95
d.0.80
e.1.75
14.Beryllium occurs naturally in the form of beryl. The metal is produced from its ore by electrolysis after the ore has been converted to the oxide and then to the chloride. How many grams of Be(s) is deposited from a BeCl2 solution by a current of 5.0 A that flows for 1.0 h? (Atomic weight: Be = 9)
a.1.68
b.1.42
c.1.24
d.1.08
e.0.84
15.A proposed battery involves the reaction of Zn(s) and Cl2 (g) to give ZnCl2. If the battery is to deliver 1.5 A for 25 hours, what mass (g) of zinc must the anode contain? (Atomic weight: Zn = 65.4)
a.91
b.82
c.64
d.46
e.35
16.Electrolysis can be used to determine atomic masses. A current of 0.450 A deposits 0.786 g of a certain metal in 50.0 minutes. Calculate the atomic mass of the metal if n = 2.
a.48
b.65
c.91
d.112
e.201
17.Electrolysis can be used to determine atomic masses. A current of 0.550 A deposits 0.358 g of a certain metal in 45.0 minutes. Calculate the atomic mass of the metal if n = 3.
a.139
b.89
c.70
d.45
e.27
18.Electrolysis can be used to determine atomic masses. A current of 0.600 A deposits 2.38 g of a certain metal in exactly 1.00 hour. Calculate the atomic mass of the metal if n = 1.
a.177
b.152
c.122
d.106
e.64
19.How many minutes will it take to plate out 5.00 g of Fe from an Fe(NO3)3 solution by a current of 1.50 A? (Atomic weight: Fe = 56)
a.288
b.242
c.198
d.146
e.96.0

VOLTAIC CELL QUIZ Part II

1.The equation that represents a reaction that is not a redox reaction is ….
1. Zn + CuSO4 → ZnSO4 + Cu
2. 2H2O2 → 2H2O + O2
3. H2O + CO2 → H2CO3
4. 2H2 + O2 → 2H2O
a.Reaction 1
b.Reaction 2
c.Reaction 3
d.Reaction 4
e.All of these are redox reactions
2.For the galvanic cell described below, the correct line notation is ….
Cl2 + 2e- → 2Cl- (E0 = 1.36v)
Cu+ + e- → Cu (E0 = 0.52v)
a.Pt(s)|Cl2(g)|2Cl-(aq)||Cu(s)|Cu+(aq)
b.Pt(s)|Cu(s)|Cu+(aq)||Cl2(g)|2Cl-(aq)|Pt(s)
c.Cu(s)|Cu+(aq)||Cl2(g)|2Cl-(aq)
d.Pt(s)|Cl2(g)|2Cl-(aq)||Cu(s)|Cu+(aq)|Pt(s)
e.Cu(s)|Cu+(aq)||Cl2(g)|2Cl-(aq)|Pt(s)
3.What is indicated when a chemical cell's voltage (E) has dropped to zero?
a) The concentration of the reactants has increased.
b) The concentration of the products has decreased.
c) The cell reaction has reached equilibrium.
d) The cell reaction has completely stopped.
4.Given the redox reaction:
2 Cr(s) + 3 Cu2+(aq) --> 2 Cr3+(aq) + 3 Cu(s)
Which reaction occurs at the cathode in an electrochemical cell?
a) reduction of Cu2+(aq)
b) reduction of Cu(s)
c) oxidation of Cr3+(aq)
d) oxidation of Cr(s)
5.Given the cell reaction:
2 H2O(l)  2 H2(g) + O2(g)
The cell is best described as
a) an electrolytic cell in which an exothermic reaction occurs
b) an electrolytic cell in which an endothermic reaction occurs
c) a galvanic cell in which an exothermic reaction occurs
d) a galvanic cell in which an endothermic reaction occurs
6.In an electrochemical cell, what is the purpose of the salt bridge?
a) It is the anode.
b) It is the cathode.
c) It permits the migration of ions between the half-cells.
d) It permits the mixing of solutions between the half-cells.
7.In a voltaic cell what type of ions move toward the cathode?
a. anions
b. cations
c. neither cations nor anions
d. freons
e. both cations and anions
8.What is the equation for the net cell reaction for the electrochemical cell:
Pb(s) | PbI2(s) | HI(aq) | H2(g) | Pt(s)
a. Pb(s) + 2I-(aq) --> PbI2(s) + 2e-
b. 2H+(aq) + 2e- --> H2(g)
c. Pb(s) + 2HI(aq) --> PbI2(s) + H2
d. both a and b
e. none of the above
9.Referring to the table of Standard Cell Potentials below, determine the standard cell potential for the following reaction running in this direction:
2 Fe3+(aq) + Zn(s) --> 2 Fe2+(s) + Zn2+(aq)
a) -2.30 V
b) +0.01 V
c) +0.78 V
d) +1.53 V
e) +2.30 V
STANDARD REDUCTION POTENTIALS E°(volts)
F2 + 2 e- ---> 2 F- E0 = +2.87
Au+ + e- ---> Au Eo = +1.69
Ag+ + e- ---> Ag Eo = +0.80
Fe3+ + e- ---> Fe2+ Eo = +0.77
Cu2+ + 2 e- ---> Cu Eo = +0.34
2 H+ + 2 e- ---> H2 Eo = 0
Pb2+ + 2 e- ---> Pb Eo = -0.13
Fe2+ + 2 e- ---> Fe Eo = -0.44
Zn2+ + 2 e- ---> Zn Eo = -0.76
Na+ + e- ---> Na Eo = -2.71
Li+ + e- ---> Li Eo = -3.05
10.Which of the following metal ions in aqueous solution is most easily oxidized to its aqueous ionic form?
a) Na
b) Pb
c) Zn
d) Ag
11.Which metal is used as a coating on steel to limit corrosion?
a) Na
b) Ca
c) K
d) Zn
12.Given the nickel-cadmium battery reaction:
2 NiOOH + Cd + 2 H2O --> 2 Ni(OH)2 + Cd(OH)2
What occurs during discharge in the nickel-cadmium battery?
a) Ni3+ is reduced to Ni2+.
b) Ni2+ is reduced to Ni3+.
c) Ni3+ is oxidized to Ni2+.
d) Ni2+ is oxidized to Ni3+.
13.Referring to the table of standard cell potentials attached, determine the standard cell potential of the following reaction for the corrosion of iron in an acidic environment:
Fe(s) + 2 H+(aq) +1/2 O2(g) --> Fe2+(aq) + H2O(l)
a) +0.44 V
b) +0.79 V
c) -0.79 V
d) +1.23 V
e) +1.67 V
14.Which ion in solution is most easily reduced to its elemental form?
a) Na+
b) Cu2+
c) Mg2+
d) Zn2+
15.In the alkaline energy cell the overall reaction is: Zn(s) + 2MnO2 (s) +2 H2O ---> Zn(OH)2(s) + 2MnO(OH) (s). Which of the following half-reactions is taking place at the cathode?
a) Zn2+(aq) + 2e- ---> Zn(s)
b) Zn(s) ---> Zn2+(aq) + 2e-
c) Zn(s) + 2OH-(aq)  Zn(OH)2(s) + 2e-
d) 2 MnO2(s) +2 H2O + 2e- ---> 2MnO(OH)(s) + 2OH- (aq)
16.In the lead storage battery the product of both the cathode and anode reactions is?
a) PbSO4
b) PbO2
c) Pb
d) H2SO4
17.The fuel cell we discussed in class forms the following product:
a) H2
b) H2SO4
c) H2O
d) H2S
e) O2
18.In an alkaline energy cell the overall cell reaction is as follows:
Zn(s) + 2 MnO2(s) + 2 H2O --> Zn(OH)2(s) + 2 MnO(OH)
Which of the following reactions is taking place at the cathode?
a) 2 MnO2(s) + 2 H2O + 2e- --> Zn(OH)2(s) + 2 MnO(OH)(s)
b) 2 MnO2(s) + 2 H2O + 2e- --> 2 MnO(OH)(s) + 2 OH-
c) Zn(s) + 2 OH-(aq) --> Zn(OH)2(s) + 2e-
d) Zn(OH)2(s) + 2e-  Zn(s) + 2 OH-(aq)
19.In a Nickel-Cadmium cell the following overall reaction is taking place:
Cd(s) + NiO2(s) + 2 H2O Cd(OH)2(s) + Ni(OH)3(s)
Which of the following half-reactions are taking place at the anode?
a) NiO2(s) + 2 H2O + 2e- --> Ni(OH)2(s) + 2 OH-
b) Cd(s) + 2 OH-(aq) --> Cd(OH)2(s) + 2e-
c) Cd(OH)2(s) + 2e- --> Cd(s) + 2 OH-(aq)
d) Ni(OH)2(s) + 2 OH- --> NiO2(s) + 2 H2O + 2e-

VOLTAIC CELL QUIZ Part I

1.If the two half-cells below were combined, what would be the correct chemical equation to represent the spontaneous REDOX process?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
(A) Cu2+ + H+ ==> 1/2 H2 + Cu
(B) Cu2+ + 2H+ ==> H2 + Cu
(C) Cu2+ + 1/2 H2 ==> H+ + Cu
(D) Cu2+ + H2 ==> 2H+ + Cu
(E) Cu + 2H+ ==> H2 + Cu2+
2.If the two half-cells below were combined, what would be the voltage generated by the spontaneous REDOX process?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
(A) +0.34V
(B) -0.34V
(C) 0.00V
(D) +0.68V
(E) -0.68V
3.If the two half-cells below were combined, which cell would undergo reduction?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
(A) Hydrogen half-cell
(B) Neither
(C) Both
(D) Copper half-cell
(E) Not enough information to tell
4.If the two half-cells below were combined, what would be the expected products of the spontaneous chemical reaction?
Zn2+ + 2e- <====> Zn (-0.76V)
H+ + e- <====> 1/2 H2 (0.00V)
(A) H+ and Zn2+
(B) H+ and Zn
(C) Zn and H2
(D) H2 and Zn2+
(E) None of the above
5.Which of the following statements is FALSE?
(A) Oxidation involves a loss of electrons
(B) Reduction involves a gain of electrons
(C) In the cell, electric current flows from a positive pole
(D) A spontaneous REDOX reaction has a positive Ecell voltage
(E) Metal can be used for salt bridge
6.The following REDOX reactions all have positive Ecell voltages.
Cl2 + 2Br- ==> Br2 + 2Cl-
Br2 + 2I- ==> I2 + 2Br-
Cl2 + 2I- ==> I2 + 2Cl-
Which is the correct order of strength of oxidizing agent, from weakest to strongest?
(A) Chlorine < Iodine < Bromine
(B) Bromine < Chlorine < Iodine
(C) Iodine < Bromine < Chlorine
(D) Chlorine < Bromine < Iodine
(E) Iodine < Chlorine < Bromine
7.The standard reduction potential for Zn2+ + 2e- ==> Zn, is -0.76 V, and the standard reduction potential for Fe3+ + e- ==> Fe2+, is +0.77V. What is the Ecell for the reaction below?
2Fe3+ + Zn ==> Zn2+ + 2Fe2+
(A) +2.30V
(B) +1.53V
(C) -2.30V
(D) -1.53V
(E) -0.75V
8.Iron rusts when it comes into contact with water and oxygen. The change that the iron undergoes can be summarized thus; Fe ==> Fe2+ + 2e-. When iron metal is coated with solid zinc in a process called galvanizing, the oxidation of iron is prevented even if the zinc coating does not completely cover the iron metal. Which of the following statements serves best to explain these observations?
(A) Solid zinc metal is more easily reduced than iron
(B) Solid zinc metal is more easily oxidized than iron
(C) Zinc ions are more easily reduced than iron
(D) Zinc ions are more easily oxidized than iron
(E) Solid zinc metal is more easily reduced than iron (II) ions
9.In the spontaneous reduction of Copper (II) ions with Nickel metal to form Copper metal and Nickel (II) ions, what will happen to the Ecell value when the concentration of Copper (II) ions is increased?
Cu2+ + 2e- <====> Cu (+0.34V)
Ni2+ + 2e- <====> Ni (-0.25V)
(A) Ecell will increase
(B) Ecell will decrease
(C) Ecell will be unchanged
(D) Not enough information to tell
(E) None of the above
10.If the two half-cells below were combined, into which cell do anions from the salt bridge flow?
Cu2+ + 2e- <====> Cu (+0.34V)
H+ + e- <====> 1/2 H2 (0.00V)
(A) Hydrogen
(B) Copper
(C) Neither
(D) Cannot tell from the information given
(E) None of the above
11.What value of Ecell do you expect for
Pb(s) → Pb2+ + 2e-
in 0.015 M Pb2+ solution? E0 = +0.13 V
a.E = +0.27V
b.E = +0.83V
c.E = +0.13V
d.E = 0.00V
e.E = +0.18V
12.Reduction potential is:
a. measured in amperes
b. an intensive property
c. an extensive property
d. always positive
13.The standard hydrogen electrode is assigned a potential of ….
a.0.76 volts
b.-1.00 volts
c.1.00 volts
d.zero volts
e.mines volts
14.Calculate the value of E0cell for a galvanic cell that contains the following half cells:
Cl2 + 2e- → 2Cl- (E0 = 1.36v)
Cu+ + e- → Cu (E0 = 0.52v)
a.E0cell = 0.84 volts
b.E0cell = 1.88 volts
c.E0cell = 0.32 volts
d.E0cell = -0.32 volts
e.E0cell = -0.84 volts
15.In all electrochemical cells, the process that takes place at the anode is … and the process that takes place at the cathode is ….
a.reduction, oxidation
b.oxidation, oxidation
c.reduction, reduction
d.oxidation, reduction

THE ANSWER OF REDOX REACTION QUIZ Part III

1.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
BrO3- + Cr(OH)3 --> Br- + CrO42-
Answer : b) 4, left
2.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Zn(OH)2 + MnO2 --> Zn + MnO4-
Answer : e) 2, left
3.How many electrons are transferred in the following reaction?
2Zn(s)+Ag2O2(s)+2H2O(l)+4OH-(aq) --> 2Ag(s) + 2Zn(OH)42-(aq)
Answer : d) 4
4.How many electrons are transferred in the following reaction?
3 MnO4- + 5 Cr+ + 24 H+ --> 3 Mn2+ + 5 Cr3+ + 12 H2O
Answer : b) 2
5.How many electrons are transferred in the following reaction?
Si (s) + 4 In(OH)3 (s) + 6 OH- --> SiO32- (aq) + 4 In (s) + 9 H2O (l)
Answer : c) 12
6.Balance the following equation and determine the sum of the coefficients of the products.
NO2- + MnO4- + H2O --> NO3- + MnO2 + OH-
Answer : e) 7
7.Balance the following equation and determine the sum of the coefficients of the reactants and products.
ClO2- + MnO4- + H2O --> ClO4- + MnO2 + OH-
Answer : c)20
8.Balance the following equation and determine the sum of the coefficients of the reactants.
I- + PbO2 + H+ --> I2 + Pb2+ + H2O
Answer : c)7
9.Balance the following redox equation and indicate the coefficients of ClO3- and H2O.
IO3- + ClO3- + H+ --> I2 + ClO4- + H2O
Answer : b) 5, 1
10.Balance the following equation and indicate the coefficients of I2 and NO2.
NO3- + I2 + H+ --> IO3- + NO2 + H2O
Answer : e) 1, 4
11.Balance the following equation and indicate the coefficients of H2S and H2O. MnO4- + H2S + H+ --> Mn2+ + S + H2O
Answer : d) 5, 8
12.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
SeO42- + NO --> H2SeO3 + NO3-
Answer : c) 4, left
13.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
MnO4- + ClO3- --> Mn2+ + ClO4-
Answer : c)6, left
14.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
I2 + ClO4- --> IO3- + ClO3-
Answer : a)2, right
15.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Se + P --> PH3 + Se
Answer : d)6, right
16.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
BrO3- + Cr(OH)3 --> Br- + CrO42-
Answer : d)4, left
17.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Zn(OH)2 + MnO2 --> Zn +MnO4-
Answer : e)2, left
18.How many electrons are transferred in the following reaction?
2Zn(s)+Ag2O2(s)+2H2O(l)+4OH-(aq) --> 2Ag(s) + 2Zn(OH)42-(aq)
Answer : d)4
19.How many electrons are transferred in the following reaction?
3 MnO4- + 5 Cr+ + 24 H+ --> 3 Mn2+ + 5 Cr3+ + 12 H2O
Answer : b)2
20.How many electrons are transferred in the following reaction?
3Si(s) + 4In(OH)3(s) + 6OH- --> SiO32- (aq) + 4In(s) + 9H2O(l)
Answer : c)12
21.Dichromate (VI) ions in acid solution can be used as oxidizing agents. In the reduction half-reaction they are converted to Chromium (III) ions. When the half-reaction is balanced using the lowest possible integers, what is the sum of the coefficients?
Answer : b)29
22.Manganate (VII) ions in acid solution can be used as oxidizing agents. In the reduction half-reaction they are converted to Manganese (II) ions. When the half-reaction is balanced using the lowest possible integers, what is the sum of the coefficients?
Answer : b)18
23.How many electrons are being transferred in the reaction below?
MnO4- + Fe + 2H2O ==> Fe3+ + MnO2 + 4OH-
Answer : d)3
24.How many electrons are being transferred in the REDOX reaction below?
Br2 + 2I- ==> 2Br- + I2
Answer : c)2
25.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
BrO3- + Cr(OH)3 --> Br- + CrO42-
Answer : b)4, left
26.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Zn(OH)2 + MnO2 --> Zn + MnO4-
Answer : e)2, left
27.How many electrons are transferred in the following reaction?
2Zn(s)+Ag2O2(s)+2H2O(l)+4OH-(aq) --> 2Ag(s) + 2Zn(OH)42-(aq)
Answer : d)4
28.How many electrons are transferred in the following reaction?
3 MnO4- + 5 Cr+ + 24 H+ --> 3 Mn2+ + 5 Cr3+ + 12 H2O
Answer : b)2
29.How many electrons are transferred in the following reaction?
Si (s) + 4 In(OH)3 (s) + 6 OH- --> SiO32- (aq) + 4 In (s) + 9 H2O (l)
Answer : c)12
30.Balance the following equation and determine the sum of the coefficients of the products.
NO2- + MnO4- + H2O --> NO3- + MnO2 + OH-
Answer : e)7
31.Balance the following equation and determine the sum of the coefficients of the reactants and products.
ClO2- + MnO4- + H2O --> ClO4- + MnO2 + OH-
Answer : c)20
32.Balance the following equation and determine the sum of the coefficients of the reactants.
I- + PbO2 + H+ --> I2 + Pb2+ + H2O
Answer : c)7
33.Balance the following redox equation and indicate the coefficients of ClO3- and H2O.
IO3- + ClO3- + H+ --> I2 + ClO4- + H2O
Answer : b)5, 1
34.Balance the following equation and indicate the coefficients of I2 and NO2.
NO3- + I2 + H+ --> IO3- + NO2 + H2O
Answer : e)1, 4
35.Balance the following equation and indicate the coefficients of H2S and H2O.
MnO4- + H2S + H+ --> Mn2+ + S + H2O
Answer : d)5, 8
36.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
SeO42- + NO --> H2SeO3 + NO3-
Answer : c)4, left
37.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
MnO4- + ClO3- --> Mn2+ + ClO4-
Answer : c)6, left
38.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
I2 + ClO4- --> IO3- + ClO3-
Answer : a)2, right
39.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Se + P --> PH3 + Se
Answer : d)6, right
40.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
BrO3- + Cr(OH)3 --> Br- + CrO42-
Answer : d)4, left
41.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Zn(OH)2 + MnO2 --> Zn +MnO4-
Answer : e)2, left
42.How many electrons are transferred in the following reaction?
2Zn(s)+Ag2O2(s)+2H2O(l)+4OH-(aq) --> 2Ag(s) + 2Zn(OH)42-(aq)
Answer : d)4
43.How many electrons are transferred in the following reaction?
3 MnO4- + 5 Cr+ + 24 H+ --> 3 Mn2+ + 5 Cr3+ + 12 H2O
Answer : b)2
44.How many electrons are transferred in the following reaction?
3Si(s) + 4In(OH)3(s) + 6OH- --> SiO32- (aq) + 4In(s) + 9H2O(l)
Answer : c)12
45.Dichromate (VI) ions in acid solution can be used as oxidizing agents. In the reduction half-reaction they are converted to Chromium (III) ions. When the half-reaction is balanced using the lowest possible integers, what is the sum of the coefficients?
Answer : b)29
46.Manganate (VII) ions in acid solution can be used as oxidizing agents. In the reduction half-reaction they are converted to Manganese (II) ions. When the half-reaction is balanced using the lowest possible integers, what is the sum of the coefficients?
Answer : b)18
47.How many electrons are being transferred in the reaction below?
MnO4- + Fe + 2H2O ==> Fe3+ + MnO2 + 4OH-
Answer : d)3
48.How many electrons are being transferred in the REDOX reaction below?
Br2 + 2I- ==> 2Br- + I2
Answer : c)2

THE ANSWER OF REDOX REACTION QUIZ Part II

1.Which of the following species is a strong reducing agent?
Answer : a)Na
2.Which of the following species is a strong oxidizing agent?
Answer : e)Cr2O72-
3.Which of the following would be the best reducing agent?
Answer : d)Na
4.How many electrons are transferred in the following reaction?
2NaCl + 2H2SO4 + MnO2 → Na2SO4 + MnSO4 + 2H2O + Cl2
Answer : d)2
5.Given the reaction:
2 Al(s) + 3 Ni2+(aq)--> 2 Al3+(aq) + 3 Ni(s)
What is the total number of moles of electrons lost by 2 moles of Al(s)?
Answer : d)6
6.Given the balanced reaction:
2Al(s) + 6H+(aq) --> 2Al3+(aq) + 3 H2(aq)
What is the total number of moles of electrons gained by H+(aq) when 2 moles of Al(s) is completely reacted?
Answer : d)6
7.Balance the following equation and determine the sum of the coefficients of the reactants and products.
KClO +KMnO4 +H2O --> KClO3 +MnO2 +KOH
Answer : b)20
8.Balance the following equation and determine the sum of the coefficients of the reactants.
HCl + PbO2 --> Cl2 +PbCl2 + H2O
Answer : c.7
9.Balance the following redox equation and indicate the coefficients of NaClO3 and H2O.
IO3- + ClO3- +H+ --> I2 + ClO4- +H2O
Answer : c)5, 1
10.Balance the following equation and indicate the coefficients of I2 and NO2.
NO3- + I2 + H+ --> IO3- + NO2 + H2O
Answer : c)1, 4
11.Balance the following equation and indicate the coefficients of H2S and H2O. MnO4- + H2S + H+ --> Mn2+ + S + H2O
Answer : c)5, 8
12.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
SeO42- + NO --> H2SeO3 + NO3-
Answer : b) 4, left
13.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
MnO4- + ClO3- --> Mn2+ + ClO4-
Answer : b)6, left
14.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
I2 + ClO4- --> IO3- + ClO3-
Answer : b)2, right
15.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Se + P --> PH3 + Se
Answer : e)6, right
16.Which of the following species is a strong reducing agent?
Answer : a)Na
17.Which of the following species is a strong oxidizing agent?
Answer : e)Cr2O72-
18.Which of the following would be the best reducing agent?
Answer : a.Na
19.How many electrons are transferred in the following reaction?
2NaCl + 2H2SO4 + MnO2 → Na2SO4 + MnSO4 + 2H2O + Cl2
Answer : a.2
20.Given the reaction:
2 Al(s) + 3 Ni2+(aq)--> 2 Al3+(aq) + 3 Ni(s)
What is the total number of moles of electrons lost by 2 moles of Al(s)?
Answer : d)6
21.Given the balanced reaction:
2Al(s) + 6H+(aq) --> 2Al3+(aq) + 3 H2(aq)
What is the total number of moles of electrons gained by H+(aq) when 2 moles of Al(s) is completely reacted?
Answer : d)6
22.Balance the following equation and determine the sum of the coefficients of the reactants and products.
KClO +KMnO4 +H2O --> KClO3 +MnO2 +KOH
Answer : b)20
23.Balance the following equation and determine the sum of the coefficients of the reactants.
HCl + PbO2 --> Cl2 +PbCl2 + H2O
Answer : c) 7
24.Balance the following redox equation and indicate the coefficients of NaClO3 and H2O.
IO3- + ClO3- +H+ --> I2 + ClO4- +H2O
Answer : c)5, 1
25.Balance the following equation and indicate the coefficients of I2 and NO2.
NO3- + I2 + H+ --> IO3- + NO2 + H2O
Answer : c)1, 4
26.Balance the following equation and indicate the coefficients of H2S and H2O.
MnO4- + H2S + H+ --> Mn2+ + S + H2O
Answer : c)5, 8
27.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
SeO42- + NO --> H2SeO3 + NO3-
Answer : b)4, left
28.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
MnO4- + ClO3- --> Mn2+ + ClO4-
Answer : b)6, left
29.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
I2 + ClO4- --> IO3- + ClO3-
Answer : b)2, right
30.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Se + P --> PH3 + Se
Answer : e)6, right

THE ANSWER OF REDOX REACTION QUIZ Part I

1.Which substance is being oxidized in the following reaction?
2HCl(aq) + Zn(s) --> ZnCl2(aq) + H2(g)
Answer : c) Zn(s)
2.What is the oxidation number of Cr in K2Cr2O7?
Answer : d) +6
3.Given the following incomplete redox reaction, balance this equation in ACID solution with the set of smallest whole number coefficient:
Zn(s) + NO3-(aq) --> Zn2+(aq) + N2(g)
Identify the CORRECT statement below:
Answer : b) Zn(s) and NO3- react in a 5 to 2 mole ratio, respectively.
4.Which oxidation number is INCORRECTLY identified?
Answer : a) the oxidation number of P in phosphorus acid, H3PO3is +5
5.Which of the following is the INCORRECT statement?
Answer : c) The oxidizing agent in a redox reaction is oxidized.
6.In the reaction below, the oxidizing agent is ….
2NaCl + 2H2SO4 + MnO2 → Na2SO4 + MnSO4 + 2H2O + Cl2
Anawer : a.Mn4+
7.Which substance is being reduced in the following reaction?
14H+(aq) + Cr2O72- (aq) + 6Fe2+(aq) --> 2Cr3+(aq) + 6Fe3+(aq) + 7 H2O
Answer : e)Cr2O72-
8.Given the reaction:
4 HCl(aq) + MnO2(s)--> MnCl2(aq) + 2 H2O(l) + Cl2(g)
The manganese is ….
Answer : a) reduced and its oxidation number changes from +4 to +2
9.Given the reaction:
Pb(s) + Cu2+(aq) --> Pb2+(aq) + Cu(s)
What is the reducing agent?
Answer : c) Pb(s)
10.What occurs when an atom is oxidized in a chemical reaction?
Answer : b)a loss of electrons and an increase in oxidation number
11.Given the reaction:
3 Sn4+(aq) + 2 Cr(s) --> 3 Sn2+(aq) + 2 Cr3+(aq)
Which half-reaction represents the reduction that occurs?
Answer : a)Sn4+(aq) + 2 e- --> Sn2+(aq)
12.Given the reaction:
Zn(s) + 2 HCl(aq) --> ZnCl2(aq) + H2(g)
Which substance is oxidized?
Answer : a) Zn(s)
13.A redox reaction always demonstrates the conservation of ….
Answer : c)both mass and charge
14.Given the redox reaction:
Mg(s) + CuSO4(aq)--> MgSO4(aq) + Cu(s)
Which species acts as the oxidizing agent?
Answer : b) Cu2+(aq)
15.Which of the following ions is the weakest oxidizing agent?
Answer : d)Ba2+
16.Which substance is being oxidized in the following reaction?
2HCl(aq) + Zn(s) --> ZnCl2(aq) + H2(g)
Answer : c)Zn(s)
17.What is the oxidation number of Cr in K2Cr2O7?
Answer : d)+6
18.Given the following incomplete redox reaction, balance this equation in ACID solution with the set of smallest whole number coefficient:
Zn(s) + NO3-(aq) --> Zn2+(aq) + N2(g)
Identify the CORRECT statement below:
Answer : b)Zn(s) and NO3- react in a 5 to 2 mole ratio, respectively.
19.Which oxidation number is INCORRECTLY identified?
Answer : a)the oxidation number of P in phosphorus acid, H3PO3is +5
20.Which of the following is the INCORRECT statement?
Answer : c)The oxidizing agent in a redox reaction is oxidized.
21.In the reaction below, the oxidizing agent is ….
2NaCl + 2H2SO4 + MnO2 → Na2SO4 + MnSO4 + 2H2O + Cl2
Answer : a.Mn4+
22.Which substance is being reduced in the following reaction?
14H+(aq) + Cr2O72- (aq) + 6Fe2+(aq) --> 2Cr3+(aq) + 6Fe3+(aq) + 7 H2O
Answer: e)Cr2O72-
23.Given the reaction:
4 HCl(aq) + MnO2(s)--> MnCl2(aq) + 2 H2O(l) + Cl2(g)
The manganese is ….
Answer : a)reduced and its oxidation number changes from +4 to +2
24.Given the reaction:
Pb(s) + Cu2+(aq) --> Pb2+(aq) + Cu(s)
What is the reducing agent?
Answer: c)Pb(s)
25.What occurs when an atom is oxidized in a chemical reaction?
Answer : b)a loss of electrons and an increase in oxidation number
26.Given the reaction:
3 Sn4+(aq) + 2 Cr(s) --> 3 Sn2+(aq) + 2 Cr3+(aq)
Which half-reaction represents the reduction that occurs?
Answer : a)Sn4+(aq) + 2 e- --> Sn2+(aq)
27.Given the reaction:
Zn(s) + 2 HCl(aq) --> ZnCl2(aq) + H2(g)
Which substance is oxidized?
Answer : a)Zn(s)
28.A redox reaction always demonstrates the conservation of ….
Answer : c)both mass and charge
29.Given the redox reaction:
Mg(s) + CuSO4(aq)--> MgSO4(aq) + Cu(s)
Which species acts as the oxidizing agent?
Answer : b)Cu2+(aq)
30.Which of the following ions is the weakest oxidizing agent?
Answer : d)Ba2+

REDOX REACTION

Students,
Please remember about Redox reaction that you have learnt before. What do you think about this type of reaction? Redox comes from the words reduction and oxidation. Do you remember the reason? Please give an example of this reaction from daily life that happened around you.

Oxidation comes from the word oxigen. So, if an element reacts with oxigen, the result is an oxide, metal oxide or non metal oxide. If the metal is iron and the non metal is sulfur, please try to write down the chemical equation.

Here, I give you other examples, that is magnesium as a metal and hydrogen as a non metal.
2 Mg(s) + O2(g) --> 2 MgO(s)
2 H2(g) + O2(g) --> 2 H2O(l)

In these two reactions, Mg and H2 are oxidised by O2 and as a result, magnesium oxide and hydrogen oxide or water. So these reactions can be classified as oxidation, according to the Mg and H2. In this process, oxidation number (ON) of Mg and H change from zero to +2 and +1. Do you remember how to calculate ON?

These are a few rules to remember
1.The oxidation number of an element is zero.
2.The oxidation number of an ion is equal to the charge of the ion.
3.Hydrogen has an oxidation number of +1 (this doesn't apply to hydrides when hydrogen is -1).
4.Oxygen has an oxidation number of -2 (except in peroxides when it is -1).
It is then simply a matter of adding together all of the oxidation numbers of the elements in a compound and making sure that the total is = 0

If you look at O2, you can find that ON of O2 in both reactions change from zero to -2. Please compare the change of ON of Mg and H2 with O2. The ON of Mg and H2increase, but the ON of O2 decreases. The first reaction we call oxidation, and the second is reduction. So that reduction and oxidation occur in the same time, one transfers electrons to another. That is why these two half-reactions can not be separated.

Oxidation is the loss of electrons, reduction is the gain of electrons
Oxidation is a half equation 2 Mg --> 2 Mg2+ + 4e-.
Reduction is a half equation O2 + 4e- --> 2 O2-.

Oxidising and reducing agents
An oxidizing agent is an element which causes oxidation (and is reduced as a result) by removing electrons from another species.
A reducing agent is an element which causes reduction (and is oxidized as a result) by giving electrons to another species.
In the above example Mg is the reducing agent as it has brought about the reduction of O2 to O2-.

Students, I hope all the above explanation can help you to remember REDOX reaction and apply it to the next concept, that is balancing redox equation.

REDOX REACTION QUIZ Part III

1.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
BrO3- + Cr(OH)3 --> Br- + CrO42-
a)5, left
b)4, left
c)2, left
d)4, right
e)2 ,right
2.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Zn(OH)2 + MnO2 --> Zn + MnO4-
a)4 ,right
b)2, right
c)5, left
d)4, left
e)2, left
3.How many electrons are transferred in the following reaction?
2Zn(s)+Ag2O2(s)+2H2O(l)+4OH-(aq) --> 2Ag(s) + 2Zn(OH)42-(aq)
a)1
b)2
c)3
d)4
e)6
4.How many electrons are transferred in the following reaction?
3 MnO4- + 5 Cr+ + 24 H+ --> 3 Mn2+ + 5 Cr3+ + 12 H2O
a)1
b)2
c)3
d)4
e)5
5.How many electrons are transferred in the following reaction?
Si (s) + 4 In(OH)3 (s) + 6 OH- --> SiO32- (aq) + 4 In (s) + 9 H2O (l)
a)10
b)11
c)12
d)14
e)16
6.Balance the following equation and determine the sum of the coefficients of the products.
NO2- + MnO4- + H2O --> NO3- + MnO2 + OH-
a)3
b)4
c)5
d)6
e)7
7.Balance the following equation and determine the sum of the coefficients of the reactants and products.
ClO2- + MnO4- + H2O --> ClO4- + MnO2 + OH-
a)14
b)16
c)20
d)18
e)22
8.Balance the following equation and determine the sum of the coefficients of the reactants.
I- + PbO2 + H+ --> I2 + Pb2+ + H2O
a)5
b)6
c)7
d)8
e)9
9.Balance the following redox equation and indicate the coefficients of ClO3- and H2O
IO3- + ClO3- + H+ --> I2 + ClO4- + H2O
a)5, 2
b)5, 1
c)4, 1
d)3, 2
e)3, 1
10.Balance the following equation and indicate the coefficients of I2 and NO2.
NO3- + I2 + H+ --> IO3- + NO2 + H2O
a)2, 6
b)2, 5
c)2, 4
d)1, 6
e)1, 4
11.Balance the following equation and indicate the coefficients of H2S and H2O.
MnO4- + H2S + H+ --> Mn2+ + S + H2O
a)2, 4
b)2, 6
c)3, 8
d)5, 8
e)5, 10
12.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
SeO42- + NO --> H2SeO3 + NO3-
a)8, left
b)6, left
c)4, left
d)6, right
e)4, right
13.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
MnO4- + ClO3- --> Mn2+ + ClO4-
a)6, right
b)4, right
c)6, left
d)4, left
e)2, right
14.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
I2 + ClO4- --> IO3- + ClO3-
a)2, right
b)4, right
c)6, right
d)6, left
e)4, left
15.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Se + P --> PH3 + Se
a)4, left
b)4, right
c)6, left
d)6, right
e)8, right
16.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
BrO3- + Cr(OH)3 --> Br- + CrO42-
a)2, left
b)2, right
c)4 ,right
d)4, left
e)5, left
17.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Zn(OH)2 + MnO2 --> Zn +MnO4-
a)4 ,right
b)2, right
c)5, left
d)4, left
e)2, left
18.How many electrons are transferred in the following reaction?
2Zn(s)+Ag2O2(s)+2H2O(l)+4OH-(aq)--> 2Ag(s) + 2Zn(OH)42-(aq)
a)1
b)2
c)3
d)4
e)6
19.How many electrons are transferred in the following reaction?
3 MnO4- + 5 Cr+ + 24 H+ --> 3 Mn2+ + 5 Cr3+ + 12 H2O
a)1
b)2
c)3
d)4
e)5
20.How many electrons are transferred in the following reaction?
3Si(s) + 4In(OH)3(s) + 6OH- --> SiO32- (aq) + 4In(s) + 9H2O(l)
a)10
b)11
c)12
d)14
e)16

REDOX REACTION QUIZ Part II

1.Which of the following species is a strong reducing agent?
a) Na
b) Na+
c) H2
d) H+
e) Cr2O72-
2.Which of the following species is a strong oxidizing agent?
a) Na
b) Na+
c) H2
d) H+
e) Cr2O72-
3.Which of the following would be the best reducing agent?
a.O2-
b.F-
c.Cl2
d.Na
e.Na+
4.How many electrons are transferred in the following reaction?
2NaCl + 2H2SO4 + MnO2 → Na2SO4 + MnSO4 + 2H2O + Cl2
a.8
b.6
c.4
d.2
e.1
5.Given the reaction:
2 Al(s) + 3 Ni2+(aq)--> 2 Al3+(aq) + 3 Ni(s)
What is the total number of moles of electrons lost by 2 moles of Al(s)?
a) 1
b) 2
c) 3
d) 6
e) 8
6.Given the balanced reaction:
2Al(s) + 6H+(aq) --> 2Al3+(aq) + 3 H2(aq)
What is the total number of moles of electrons gained by H+(aq) when 2 moles of Al(s) is completely reacted?
a) 2
b) 3
c) 4
d) 6
e)12
7.Balance the following equation and determine the sum of the coefficients of the reactants and products.
KClO +KMnO4 +H2O --> KClO3 +MnO2 +KOH
a)16
b)20
c)14
d)22
e)18
8.Balance the following equation and determine the sum of the coefficients of the reactants.
HCl + PbO2 --> Cl2 +PbCl2 + H2O
a)5
b)6
c)7
d)8
e)9
9.Balance the following redox equation and indicate the coefficients of NaClO3 and H2O.
IO3- + ClO3- +H+ --> I2 + ClO4- +H2O
a)5, 2
b)3, 2
c)5, 1
d)3, 1
e)4, 1
10.Balance the following equation and indicate the coefficients of I2 and NO2.
NO3- + I2 + H+ --> IO3- + NO2 + H2O
a)2, 6
b)2, 4
c)1, 4
d)1, 6
e)2, 5
11.Balance the following equation and indicate the coefficients of H2S and H2O.
MnO4- + H2S + H+ --> Mn2+ + S + H2O
a)3, 8
b)2, 4
c)5, 8
d)5, 10
e)2, 6
12.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
SeO42- + NO --> H2SeO3 + NO3-
a)8, left
b)4, left
c)6, right
d)4, right
e)6, left
13.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
MnO4- + ClO3- --> Mn2+ + ClO4-
a)4, left
b)6, left
c)6, right
d)4, right
e)2, right
14.Balance the following equation in acidic solution and determine the coefficient of H+ and its location (right or left side) in the equation.
I2 + ClO4- --> IO3- + ClO3-
a)4, right
b)2, right
c)6, left
d)4, left
e)6, right
15.Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
Se + P --> PH3 + Se
a)8, right
b)4, left
c)4, right
d)6, left
e)6, right

REDOX REACTION QUIZ Part I

1.Which substance is being oxidized in the following reaction?
2HCl(aq) + Zn(s)  ZnCl2(aq) + H2(g)
a) H+(aq) ions
b) Cl-(aq) ions
c) Zn(s)
d) Zn2+(aq) ions
e) H2(g)
2.What is the oxidation number of Cr in K2Cr2O7?
a) +2
b) +3
c) +5
d)+6
e)+7
3.Given the following incomplete redox reaction, balance this equation in ACID solution with the set of smallest whole number coefficient:
Zn(s) + NO3-(aq)  Zn2+(aq) + N2(g)
Identify the CORRECT statement below:
a) Zn(s) and NO3- react in a 1 to 2 mole ratio, respectively.
b) Zn(s) and NO3- react in a 5 to 2 mole ratio, respectively.
c) Zn(s) and NO3- react in a 2 to 5 mole ratio, respectively.
d) Zn(s) and NO3- react in a 5 to 1 mole ratio, respectively.
4.Which oxidation number is INCORRECTLY identified?
a) the oxidation number of P in phosphorus acid, H3PO3is +5
b) the oxidation number of H in sodium hydride NaH is -1
c) the oxidation number of O in water is -2
d) the oxidation number of Mn in manganic acid, HMnO4 is +7
5.Which of the following is the INCORRECT statement?
a) Oxidation results in an increase in oxidation number.
b) Electrons are being transferred in a redox reaction.
c) The oxidizing agent in a redox reaction is oxidized.
d) Reduction is a gain of electrons.
6.In the reaction below, the oxidizing agent is ….
2NaCl + 2H2SO4 + MnO2 → Na2SO4 + MnSO4 + 2H2O + Cl2
a)Na+
b)Mn4+
c)Cl-
d)H+
e)O2-
7.Which substance is being reduced in the following reaction?
14H+(aq) + Cr2O72- (aq) + 6Fe2+(aq)  2Cr3+(aq) + 6Fe3+(aq) + 7 H2O
a) H+(aq)
b) Fe2+(aq)
c) H2O
d) Cr3+(aq)
e) Cr2O72-
8.Given the reaction:
4 HCl(aq) + MnO2(s) MnCl2(aq) + 2 H2O(l) + Cl2(g)
The manganese is ….
a) reduced and its oxidation number changes from +4 to +2
b) reduced and its oxidation number changes from +2 to +4
c) oxidized and its oxidation number changes from +4 to +2
d) oxidized and its oxidation number changes from +2 to +4
9.Given the reaction:
Pb(s) + Cu2+(aq)  Pb2+(aq) + Cu(s)
What is the reducing agent?
a) Pb2+(aq)
b) Cu2+(aq)
c) Pb(s)
d) Cu(s)
e) Pb(s) and Cu(s)
10.What occurs when an atom is oxidized in a chemical reaction?
a) a loss of electrons and a decrease in oxidation number
b) a loss of electrons and an increase in oxidation number
c) a gain of electrons and a decrease in oxidation number
d) a gain of electrons and an increase in oxidation number
11.Given the reaction:
3 Sn4+(aq) + 2 Cr(s)  3 Sn2+(aq) + 2 Cr3+(aq)
Which half-reaction represents the reduction that occurs?
a) Sn4+(aq) + 2 e-  Sn2+(aq)
b) Sn2+(aq)  Sn4+(aq) + 2 e-
c) Cr(s)  Cr3+(aq) + 3 e-
d) Cr3+(aq) + 3 e-  Cr(s)
12.Given the reaction:
Zn(s) + 2 HCl(aq)  ZnCl2(aq) + H2(g)
Which substance is oxidized?
a) Zn(s)
b) HCl(aq)
c) Cl-(aq)
d) H+(aq)
e) H2(g)
13.A redox reaction always demonstrates the conservation of ….
a) mass, only
b) charge, only
c) both mass and charge
d) neither mass nor charge
e) mass, volume, and charge
14.Given the redox reaction:
Mg(s) + CuSO4(aq) MgSO4(aq) + Cu(s)
Which species acts as the oxidizing agent?
a) Cu(s)
b) Cu2+(aq)
c) Mg(s)
d) Mg2+(aq)
e) SO42-
15.Which of the following ions is the weakest oxidizing agent?
a) Au3+
b) Cr3+
c) Hg2+
d) Ba2+
e) Mg2+

THE ANSWER OF CHEMICAL BONDING QUIZ XI Part II

11.The following substances which has the lowest melting point is ….
d.butane, C4H10
Answer : e.salt, NaCl
12.Which of the following is arranged in order of increasing boiling points?
Answer : c.H2S, H2Se, H2O
13.How can the physical properties of substances be explained?
Answer : b.In terms of intermolecular forces only
14. In general, what do the physical properties of substances include?
Answer : b.conductivity, malleability, solubility, hardness, melting and boiling point only
15.The boiling point of water is about 200°C higher than one would predict from the boiling points of hydrogen sulfide and hydrogen selenide. One may explain this apparent anomaly by which of the following?
Answer : b.the intermolecular attractive forces are much greater in water than in hydrogen sulfide and hydrogen selenide.
16.The boiling point of CH4 is much lower than that of HF. This is because ….
Answer : c.of hydrogen bonding in HF
17.Based on the following information:
CF4, Molecular Weight 87.99, Normal Boiling Point -182°C
CCl4, Molecular Weight 153.8, Normal Boiling Point -123°C
The reason that CCl4 has a higher boiling point than CF4 is that ....
Answer : c.CF4 molecule have a greater polarizability
18.The wrong statement about methane, ammonia, and water is ….
Answer : e.the molecule shape of ammonia is pyramid
19.If the molecules of BF3 and NH3 are compared one of another, the correct answer is ....
Answer : b.BF3 doesn’t have lone pair electron
20.The hybridization state of PCl5 is ….
Answer : c.sp3d

THE ANSWER OF CHEMICAL BONDING QUIZ X Part III

1.Which substance contains nonpolar covalent bonds?
Answer : a. Cl2
2.Which type of substance is soft, has a low melting point, and is a poor conductor of heat and electricity?
Answer : c. molecular solid
3.Which substance contains coordinate bond?
Answer : a. NH4Cl
4.The correct answer of the dot electrons with an arrow is ….
Answer : c. co-ordinate bond
5.Which molecule is nonpolar?
Answer : b. CO2
6.Which bond has the highest degree of polarity?
Answer : a. HF
7.Which of the following molecules is polar?
Answer : c. H2S
8.Molecular polarity can be determined by the ….
Answer : c. distribution of charge
9.Which characteristic is a property of molecular substances?
Answer : a. low boiling point
10.What is used to assess the degree of polarity in the bond?
Answer : b.electronegativity difference of the two bonded atoms
11.Which of the following statements is (are) incorrect?
Answer : e. CH4 is an asymmetrical molecule
12.Metallic bond is the bond occurs between ….
Answer : d.metal
13.The correct statement about metallic bond is the bond between ….
Answer : d.positive ions of metals and electrons’ current
14.Which statement describes a chemical property of iron?
Answer : d. Iron combines with oxygen to form rust
15.The effect of electrons’ current in metal is ….
Answer : c.electrons move freely
16.Metallic bonding occurs between atoms of ….
Answer : c. copper
17.Metallic bonding occurs between metal atoms that have ….
Answer : c. vacant valence orbitals and low ionization energies
18.Which characteristic is a property of metallic substances?
Answer : d. relatively low solubility
19.Which of the following Period 4 elements has the most metallic characteristics?
Answer : a. K
20.Which of the following elements has the most metallic characteristics?
Answer : c. Na

THE ANSWER OF CHEMICAL BONDING QUIZ X Part II

1. Which substance contains a bond with the greatest ionic character?
Answer : a. KCl
2. What do ionic solids have between particles?
Answer : a. very strong ionic bonds
3. Which substance conducts electricity when melted but not when solid?
Answer : b. an ionic compound
4.An element with an electronegativity of 0.9 bonds with an element with an electronegativity of 3.1. Which phrase best describes the bond between these elements?
Answer : c.mostly covalent in character and formed between two nonmetal
5. Which compound has the highest melting point?
Answer : b. NaCl
6.Which is not an identity of the bond formed between 2 hydrogen atoms?
Answer : d.double covalent bond
7.One valence electron from each chlorine atoms are shared.How many valence electrons are shared in a double bond?
Answer (a. 2)
8.A triple bond is formed when ….
Answer : c. 3 pairs of electrons are shared.
9. In a multiple covalent bond ….
Answer : b.more than one pair of electrons is shared between two atoms.
10. HCl is formed ….
Answer : a. when 1 pair of valence electrons is shared, one from the hydrogen atom and one from the chlorine atom.
11. The electrons in the bond between hydrogen and flourine are more strongly attracted to the atom of ….
Answer : b.fluorine, which has the higher electronegativity
12. Which compound contains a covalent bond?
Answer : a. HCl
13. When a reaction occurs between atoms with electron configurations of (2,8,5) and (2,7), the bond formed is mainly ….
Answer : b. polar covalent
14. In which compound do atoms form bonds by sharing electrons?
Answer : a. H2O
15. What is the maximum number of covalent bonds that a carbon atom can form?
Answer (d. 4)
16. Which pair of bonds will share electrons when a bond is formed between them?
Answer : b. Br and Cl
17. Which substance contains nonpolar covalent bonds?
Answer : a. H2
18. Which compound contains both ionic and covalent bonding?
Answer : c. KNO3
19. Silicon dioxide (SiO2) and diamonds are best described as ….
Answer : c. network solids with covalent bonding

THE ANSWER OF CHEMICAL BONDING QUIZ X Part I

1.lewis structure of an atom shows ....
Answer : b.electrons in the outermost shell
2.How many dots are to be around Ne in its Lewis structure?
Answer (e.8)
3.Which element attains the structure of a noble gas when it becomes a 2+ ion? Answer : b.Ba
4.Which element attains the structure of a noble gas when it becomes a l+ ion?
Answer : a.K
5.How many dots would the electron dot-diagram of Mg2+ have?
Answer (b.2)
6.Which of the following atoms has the greatest tendency to attract electrons?
Answer : e.bromine
7.The distribution of charge is determined by the use of ….
Answer : e.valence shells
8.What do the following have in common? 20Ne 19F- 24Mg2+
Answer : d.They are isoelectronic with each other.
9.When bromine gains one electron it ….
Answer : b.becomes a negative ion with a larger radius
10.Which of the following substances does not belong to the major categories of compounds?
Answer : b.Li
11.In ionic bonds, nonmetals are most likely to ….
Answer : a.gain electrons
12.When a potassium atom reacts with bromine, the potassium will ….
Answer : a.lose only 1 electron
13.The negative ion F- has the same electronic configuration as the positive ion ….
Answer : c.Mg2+
14.Ionic bonds are formed when ….
Answer : b.valence electrons are transferred from one atom to another
15.When a reaction occurs between atoms with ground-state electron configurations of (2,1) and (2,7), the bond formed is mainly ….
Answer : a.ionic
16.Which compound contains ionic bonds?
Answer : b.CaO
17.Lithium and chloride react to form LiCl, an ionic compound. The chloride ion has ____ electrons in its outermost occupied shell.
Answer (d.8)
18.When a sodium atom reacts with a chlorine atom to form a compound, the electron configurations of the ions forming the compound are the same as those in which noble gas atoms?
Answer : d.neon and argon