CHEMISTRY TEST FOR RSBI XII FIRST SEMESTER

Students, I want to help you learning back the concepts that you have learnt during this semester. Please test yourself by using the following item tests. These are about colligative properties, balancing redox reaction and electrochemical cells.

1. A solution is prepared from 50.0 g of solid sucrose, C12H22O11 in 250 g of water at 25.0oC. The vapor pressure of pure water is 23.8 torr at 25oC. What is the vapor pressure of the solution? (Ar C = 12, H = 1, O = 16).
a. 22.8
b. 23.0
c. 23.3
d. 23.6
e. 23.8
2. A solution consists of 5,85 grams of table salt, NaCl (Mr = 58,5) in 800 g of water. This solution boils at the same temperature with a solution which contains of 3 g X (a non electrolyte substance) in 200 g of water. Mr of X is ….
a. 40
b. 50
c. 60
d. 80
e. 120
3. A solution prepared by dissolving x grams of nicotine (a non electrolyte) in water to make a 12 mL of solution has an osmotic pressure of 7,55 atm at 250C. The mass of nicotine is …. (Mr nicotine = 160; R = 0,082 L atm/K mol)
a. 0,20
b. 0,60
c. 0,80
d. 1,40
e. 2,80
4. Which of the following solutes will produce the highest solution boiling point when dissolved in water?
a. 1,5 moles of MgCl2
b. 2 moles of methanol
c. 3 moles of NaCl
d. 4,5 moles of urea
e. 5 moles of ethanol
5. After balancing the redox reactions below, the value of a, b, c, d, and e in order are ….
aK2C2O4 + bK2Cr2O7 + cH2SO4 à dCO2 + Cr2(SO4)3 + K2SO4 + eH2O
a. 3, 1, 7, 3, 7
b. 3, 1, 7, 6, 7
c. 3, 2, 7, 3, 7
d. 6, 2, 7, 6, 7
e. 6, 1, 7, 3, 7
6. In an electrochemical cell of Zn – Cu, what occurs when the circuit is closed?
a. Zn(s) --> Zn2+(aq) + 2e
b. Cu(s) --> Cu2+(aq) + 2e
c. 2H2O(l) --> 2H2(g) + O2(g)
d. Electrons flow from Cu to Zn.
e. Electric current flows from Zn to Cu
7. From the following listed standard electrode potentials, the biggest Eo for the cell is ….
Mg2+(aq) + 2e --> Mg(s) Eo = --2,24 V
Sn2+(aq) + 2e --> Sn(s) Eo = --0,14 V
Hg2+(aq) + 2e --> Hg(s) Eo = +0,62 V
Cu2+(aq) + 2e --> Cu(s) Eo = +0,34 V
a. Sn(s)+Hg2+(aq) --> Sn2+(aq)+Hg(s)
b. Sn(s)+Cu2+(aq) --> Sn2+(aq)+Cu(s)
c. Hg(s)+Cu2+(aq) --> Hg2+(aq)+Cu(s)
d. Mg(s)+Cu2+(aq) --> Mg2+(aq)+Cu(s)
e. Mg(s)+Hg2+(aq) --> Mg2+(aq)+Hg(s)
8. Na2SO4(aq) is electrolysed by using graphyte as electrodes. The reaction that is occured at the positive electrode is ....
a. Na(s) --> Na+(aq) + e
b. Na+(aq) + e --> Na(s)
c. 2H+(aq) + 2e --> H2(g)
d. 2H2O(l) + 2e --> H2 + 2OH-(g)
e. 2H2O(l) --> 4H+(aq) +O2(g) +4e
9. How many hours will it take to plate out 4,85 g of Cr from a Cr2(SO4)3 solution using a current of 1.50 A? (Ar Cr = 52)
a. 5
b. 4,8
c. 3
d. 2,4
e. 1,2
10. Draw the Zn - Cu cell and electrolysis cell, then explain the comparison of these two electrochemical cells.

COLLIGATIVE PROPERTIES QUIZ FOR RSBI XII Part IV

BOILING POINT AND FREEZING POINT

1.Dissolving 1 mole of KCl in 1000 grams of H2O affects
a) the boiling point of the H2O, only
b) the freezing point of the H2O, only
c) both the boiling point and the freezing point of the H2O
d) neither the boiling point nor the freezing point of the H2O
2.Which solution has the highest boiling point?
a) 1.0 M Ca(NO3)2
b) 2.0 M Ca(NO3)2
c) 1.0 M KNO3
d) 2.0 M KNO3
e) 4.0 M KNO3
3.If 4.27 grams of sucrose, C12H22O11 (molar mass = 342 g/mol), is dissolved in 15.2 grams of water, what will be the boiling point of the resulting solution? Kb for water is 0.512°C/molal. Assume the barometric pressure is 760 torr, at which pure water has a boiling point of 100.000°C.
a) 101.64°C
b) 100.42°C
c) 99.626°C
d) 100.73°C
e) 101.42°C
4.Which of the following solutes will produce the highest solution boiling point when dissolved in water?
a) 2 moles of NaCl
b) 1 mole of ethanol
c) 1 mole of MgCl2
d) 2 moles of methanol
e) 1 mole of methanol
5.Rank the following liquids in order of increasing boiling points, from lowest to highest:
n-pentane (C5H12)
hexyl alcohol (C6H13OH)
2,2-dimethylpropane (C5H12)
a) n-pentane (C5H12) < hexyl alcohol (C6H13OH) < 2,2-dimethylpropane (C5H12)
b) 2,2-dimethylpropane (C5H12) < n-pentane (C5H12) < hexyl alcohol (C6H13OH)
c) hexyl alcohol (C6H13OH) < 2,2-dimethylpropane (C5H12) < n-pentane (C5H12)
d) n-pentane (C5H12) < 2,2-dimethylpropane (C5H12) < hexyl alcohol (C6H13OH)
e) 2,2-dimethylpropane (C5H12) < hexyl alcohol (C6H13OH) < n-pentane (C5H12)
6.The boiling point of O2 is higher than N2 due to:
a) ion-dipole forces.
b) dipole-dipole forces.
c) hydrogen bonding.
d) London forces.
e) ion-ion forces.
7.Calculate the freezing point of a solution that contains 8.00 g of sucrose, C12H22O11 (molar mass = 342 g/mol), in 100.0 g of H2O. Kf for H2O is 1.86°C/molal.
a) -0.044°C
b) -0.22°C
c) -0.39°C
d) -0.44°C
e) 0.040°C
8.Which of the following solutes will produce the lowest solution freezing point when dissolved in water?
a) 2 moles of KNO3
b) 1 mole of ethanol
c) 1 mole of CaCl2
d) 2 moles of methanol
e) 1 mole of methanol
9.Calculate the mass of "antifreeze" (ethylene glycol, MW (molar mass) = 62 g/mol) necessary to mix with 80 L (80 Kg) of water in a radiator in order to make the water in the radiator freeze below 0oF (-17.8oC). Kf for water is -1.86oC/m.
a) 48 kg
b) 80 kg
c) 62 g
d) 4800g
e) 2400g
10.Which of the following solutes will produce the highest freezing point when dissolved in water?
a)4 grams of NaOH in 1L of water
b)3 grams of urea in 2L of water
c)18 grams of glucose in 500 mL of water
d)5,9 grams of NaCl in 2L of water
e)1,5 grams of acetic acid in 500 mL of water

COLLIGATIVE PROPERTIES QUIZ FOR RSBI XII Part III

VAPOR PRESSURE

1.Which of the following aqueous solutions having the indicated mole fraction of solute should have the highest vapor pressure of water assuming ideality?
a) 0.01 X(sucrose)
b) 0.005 X(Na2SO4)
c) 0.008 X(CaCl2)
d) 0.01 X(NaCl)
e) 0.007 X(Mg(OH)2)
2.Which of the following aqueous solutions having the indicated mole fraction of solute should have the lowest vapor pressure of water assuming ideality?
a) 0.02 X(sucrose) at 15oC
b) 0.01 X(NaCl) at 50oC
c) 0.008 X(CaCl2) at 25oC
d) 0.01 X(NaCl) at 25oC
e) 0.008 X(CaCl2) at 50oC
3.Which of the following aqueous solutions having the indicated mole fraction of solute should have the highest vapor pressure of water assuming ideality?
a) 0.02 X(NaCl) at 50oC
b) 0.03 X(sucrose) at 15oC
c) 0.005 X(CaCl2) at 50oC
d) 0.02 X(NaCl) at 25oC
e) 0.005 X(CaCl2) at 25oC
4.What is the vapor pressure (atm) at 40oC of a solution that contains 3.00 moles of heptane and 5.00 moles of octane? At 40oC the vapor pressure of heptane and octane are 0.121 and 0.067 atm respectively.
a) 0.067
b) 0.080
c) 0.075
d) 0.087
e) 0.061
5.What is the total vapor pressure (mm Hg) above a solution of 50.0 g of benzene, C6H6 and 50.0 g of toluene, C7H8, at 25oC. The vapor pressures of pure benzene and toluene at this temperature are 95.1 and 28.4 mm Hg respectively. Ar: C = 12, H = 1).
a) 63.8
b) 65.0
c) 63.0
d) 64.5
e) 65.6
6.What is the total pressure at 25oC of a solution of 1.0 moles of toluene (C7H8) and 2.0 moles of benzene (C6H6) at 25oC if the vapor pressures of the pure solvents are 22 and 75 mm Hg respectively at 20oC? A: C = 12, H = 1, Cl = 35.5).
a) 49
b) 36
c) 63
d) 57
e) 41
7.If the vapor pressure of water at 90° C is 0.692 atm, then what is the vapor pressure of a solution (in atm) made by dissoving 1.00 mole of urea in 1.00 kg of water?
a) 0.692
b) 0.680
c) 0.668
d) 0.656
e) 0.634
8.The vapor pressure of CH3OH at 30oC is 160 torr. What mole fraction of glycerol, C3H5(OH)3, (a nonvolatile solute) would be required to lower the vapor pressure to 130 torr? Ar: C = 12, H = 1, O = 16).
a) 0.230
b) 0.188
c) 0.198
d) 0.168
e) 0.210
9.Ethylene glycol (C2H6O2) is only slightly volatile at 100oC. Determine the vapor pressure (torr) of water at 100oC in a solution of 1.90 x 103 g of water and 625 g of ethylene glycol. The vapor pressure of pure water is 760 torr at 100oC. (Ar; C = 12, H = 1, O = 16).
a) 671
b) 694
c) 682
d) 705
e) 712
10.Sucrose, C12H22O11 (molar mass = 342 g/.mol) is a non-volatile, nonionizing solute in water. Determine the vapor pressure lowering, Pvap, at 27°C, of a solution of 75.0 grams of sucrose dissolved in 180.0 g of water. The vapor pressure of pure water at 27°C is 26.7 torr. Assume the solution is ideal.
a) 0.585 torr
b) 0.058 torr
c) 0.573 torr
d) 5.62 torr
e) 0.548 torr

COLLIGATIVE PROPERTIES QUIZ FOR RSBI XII Part II

CONCENTRATION OF SOLUTION: MOLALITY AND MOLE FRACTION

1.The density of a 56.0% by weight aqueous solution of methanol (CH3OH) is 0.9046 g/cm3. What is the molality of the compound? (Ar: C = 12, H = 1, O = 16).
a) 36.8
b) 39.7
c) 37.9
d) 40.9
e) 38.6
2.The density of a 72.0% by weight aqueous solution of ethanol (CH3CH2OH) is 0.8644 g/cm3. What is the molality of the compound? (Ar: C = 12, H = 1, O = 16).
a) 58.9
b) 55.8
c) 57.2
d) 53.0
e) 54.1
3.Concentrated HBr is 48.0% HBr by mass and has a density of 1.50 g/mL. What is the molality of this solution? (Ar: H = 1, Br = 80).
a) 12.5
b) 11.4
c) 12.2
d) 11.6
e) 11.9
4.What is the molality of a solution of 25 g of ethyl alcohol (C2H5OH) in 200.0 mL of benzene, C6H6? The density of benzene is 0.879 g/mL. (Ar: C = 12, H = 1, O = 16).
a) 4.5
b) 0.31
c) 3.1
d) 0.62
e) 0.45
5.What is the molality of a solution of 50.0 g of methyl alcohol, CH3OH, in 450.0 g of water? (Ar: C = 12, H = 1, O = 16).
a) 0.700
b) 1.73
c) 3.47
d) 0.173
e) 0.347
6.Formalin is a preservative solution used in biology laboratories. It contains 40 cm3 of formaldehyde, CH2O, (density 0.82 g/cm3) per 100 cm3 of water. What is the molality of formalin? (Ar: C = 12, H = 1, O = 16).
a) 10
b) 8.0
c) 11
d) 12
e) 9.0
7.The density of a 3.29 M aqueous solution of (NH4)2SO4 is 1.2077 g/cm3. What is the molality of the solution? (Ar: N = 14, S = 32, O = 16, H = 1).
a) 3.60
b) 4.26
c) 3.29
d) 3.82
e) 4.03
8.A solution of vinegar is 0.763 M in acetic acid, C2H4O2. The density of vinegar is 1.004 g/mL. What is the molal concentration of acetic acid?
(Ar: C = 12, H = 1, O = 16).
a) 0.751
b) 0.796
c) 0.715
d) 0.815
e) 0.730
9.The density of a 0.872 M aqueous solution of K2CrO4 is 1.129 g/cm3? What is the molality of the solution? (Ar: K = 39, Cr = 52, O = 16).
a) 0.872
b) 0.909
c) 0.232
d) 1.50
e) 0.0909
10.What is the molality of a CsCl solution with a mole fraction of 0.0967? (Ar: Cs = 133, Cl = 35.5, H = 1, O = 16).
a) 5.29
b) 5.55
c) 5.73
d) 5.95
e) 6.21
11.What is the molality of a K2CrO4 solution with a mole fraction of 0.0161? (Ar: K = 39, Cr = 52, O = 16, H = 1).
a) 0.841
b) 0.790
c) 0.820
d) 0.909
e) 0.872
12.What is the molality of a CH3OH solution with a mole fraction of 0.417? (Ar: C = 12, H = 1, O = 16).
a) 35.8
b) 37.3
c) 38.2
d) 39.7
e) 36.4
13.What is the mole fraction of CsCl in a solution prepared from 0.297 moles of CsCl and 2.78 moles of water? (Ar: Cs = 133, Cl = 35.5, H = 1, O = 16).
a) 0.105
b) 0.116
c) 0.0912
d) 0.0861
e) 0.0967
14.What is the mole fraction of CH3CH2CH2OH in a solution prepared from 0.932 moles of CH3CH2CH2OH and 2.44 moles of water? (Ar: C = 12, H = 1, O = 16).
a) 0.258
b) 0.241
c) 0.292
d) 0.227
e) 0.276
15.What is the mole fraction of Pb(NO3)2 in a solution prepared from 0.0543 moles of Pb(NO3)2 and 4.55 moles of water? (Ar: Pb = 207, N = 14, O = 16).
a) 0.129
b) 0.0129
c) 0.136
d) 0.0136
e) 0.0118
16.An automobile antifreeze solution contains 2.42 kg of ethylene glycol, HOCH2CH2OH, and 2.00 kg of water. What is the mole fraction of ethylene glycol? (Ar: C = 12, H = 1, O = 16).
a) 0.290
b) 0.710
c) 0.260
d) 0.320
e) 0.740
17.What is the mole fraction of ethanol, C2H5OH in an alcoholic beverage that is 40% ethanol and 60% water by weight? (Ar: C = 12, H = 1, O = 16).
a) 0.39
b) 0.29
c) 0.21
d) 0.71
e) 0.79
18.What is the mole fraction of C6H5OH in a solution containing 23.5 g of C6H5OH and 41.4 g of C2H5OH? (Ar: C = 12, O = 16, H = 1).
a) 0.200
b) 0.262
c) 0.217
d) 0.231
e) 0.299
19.Sterling silver contains 92.5% silver and 7.5% copper by weight. What is the mole fraction of silver? (Ar: Ag = 108, Cu = 63.5).
a) 0.88
b) 0.93
c) 0.81
d) 0.85
e) 0.94
20.Nichrome contains 80.0% nickel and 20.0% chromium by weight. What is the mole fraction of chromium? (Ar: Ni = 59, Cr = 52).
a) 0.220
b) 0.200
c) 0.160
d) 0.180
e) 0.240
21.A coin contains 90.0% silver and 10.0% copper by weight. What is the mole fraction of copper? (Ar: Ag = 108, Cu = 63.5).
a) 0.158
b) 0.115
c) 0.129
d) 0.100
e) 0.141
22.Naval brass contains 60.0% copper, 39.0% zinc and 1.0% tin by weight. What is the mole fraction of zinc? (Ar: Cu = 63.5, Zn = 65.4, Sn = 119).
a) 0.374
b) 0.385
c) 0.360
d) 0.348
e) 0.398
23.Type metal contains 82.0% lead, 15.0% antimony and 3.0% copper by weight. What is the mole fraction of copper? (Ar: Pb = 207, Sb = 122, Cu = 63.5).
a) 0.056
b) 0.083
c) 0.030
d) 0.043
e) 0.069
24.Babbitt metal contains 90.0% tin, 7.0% antimony, and 3.0 carbon by weight. What is the mole fraction of antimony? (Ar: Sn = 119, Sb = 122, C = 12).
a) 0.071
b) 0.054
c) 0.062
d) 0.045
e) 0.030
25.Babbitt metal is 69.0% zinc, 19.0% tin, 4.0% copper, 3.0% antimony and 5.0% lead by weight. What is the mole fraction of tin? (Ar: Zn = 65.4, Sn = 119, Cu = 63.5, Sb = 122, Pb = 207).
a) 0.152
b) 0.121
c) 0.190
d) 0.109
e) 0.132
26.Pewter contains 85.0% tin, 6.8% copper, 6.5% bismuth and 1.7% antimony by weight. What is the mole fraction of copper? (Ar: Sn = 119, Cu = 63.5, Bi = 209, Sb = 122).
a) 0.10
b) 0.12
c) 0.080
d) 0.068
e) 0.14
27.Pewter contains 85.0% tin, 6.8% copper, 6.5% bismuth and 1.7% antimony by weight. What is the mole fraction of bismuth? (Ar: Sn = 119, Cu = 63.5, Bi = 209, Sb = 122).
a) 0.051
b) 0.036
c) 0.059
d) 0.065
e) 0.045
28.A 10.0% by mass solution of ethanol, C2H5OH, in water has a density of 0.983 g/cm3 at 15oC. What is the mole fraction of ethanol? (Ar: C = 12, H = 1, O = 16).
a) 0.042
b) 0.065
c) 0.06
d) 0.04
e) 0.05
29.The density of a 48.0% by weight aqueous solution of H2SO4 is 1.38 g/cm3. What is the mole fraction of the compound? (Ar: H = 1, S = 32, O = 16).
a) 0.145
b) 0.178
c) 0.165
d) 0.131
e) 0.157
30.The density of a 28.0% by weight aqueous solution of H3PO4 is 1.1686 g/cm3. What is the mole fraction of the compound? (Ar: H = 1, O = 16, P = 31).
a) 0.067
b) 0.076
c) 0.072
d) 0.062
e) 0.069

COLLIGATIVE PROPERTIES QUIZ FOR RSBI XII Part I

COLLIGATIVE PROPERTIES QUIZ FOR RSBI XII FIRST SEMESTER 2009

1.The hormone adrenaline (C9H13NO3) is present in 6 mg per 100 mL of blood plasma. What is the molarity of adrenaline? (Ar C = 12, H = 1, O = 16, N = 14).
a)3 x 10-7
b)5 x 10-10
c)3 x 10-10
d)6 x 10-7
e)6 x 10-8
2.At 25oC, 0.0050 grams of NaCl dissolves in enough butanol (CH3CH2CH2CH2OH) to give 0.10 L of solution. What is the molarity of the solution? (Ar: Na = 23, Cl = 35.5, C = 12, H = 1, O = 16).
a)0.050
b)0.0009
c)0.009
d)0.0008
e)0.005
3.A solution for intravenous injections contains 300 mg of Na+ in 100.0 mL. What is the molarity of the ion? (Ar: Na = 23).
a)0.01
b)0.02
c)0.13
d)0.3
e)0.2
4.Determine the number of moles of solute present in 367 mL of 0.52 M NaClO3. (Ar: Cl = 35.5, O = 16, Na = 23).
a)0.14
b)0.11
c)0.19
d)0.09
e)0.21
5.Determine the number of moles of solute present in 127 mL of 0.12 M Na2SO4. (Ar: Na = 23, S = 32, O = 16).
a)0.018
b)0.027
c)0.016
d)0.024
e)0.031
6.How many moles of lithium chlorate (LiClO3) are in 153 mL of a 1.764 M solution?
a)0.340
b)0.210
c)0.270
d)0.240
e)0.310
7.How many grams of glucose are contained in 500.0 mL of 0.30 M glucose, C6H12O6, used in intravenous injection? (Ar: C = 12, H = 1, O = 16).
a)2.7
b)0.27
c)27
d)0.15
e)1.5
8.How many grams of CH3OH are required to prepare 50.0 mL of a 0.40 M solution? (Ar: C = 12, H = 1, O = 16).
a)0.80
b)0.45
c)0.64
d)0.50
e)0.32
9.Determine the mass (g) of solute required to form 275 mL of a 0.5151 M KClO4 solution. (Ar: K = 39, O = 16, Cl = 35.5).
a)8.59
b)12.2
c)19.6
d)4.21
e)1.97
10.A concentrated solution of K2CrO4 is 15.0% by weight and the density is 1.129 g/cm3. How many grams of the solution are required to prepare 200.0 mL of a 0.150M solution? (Ar: K = 39, Cr = 52, O = 16).
a)34.2
b)35.3
c)38.8
d)40.5
e)41.4
11.Concentrated HCl is 37.0% HCl by mass and has a density of 1.19 g/mL. How many grams of this solution are required to prepare 125 mL of a 1.50 M HCl solution? (Ar: H = 1, Cl = 35.5).
a)17.5
b)17.0
c)18.5
d)18.0
e)6.84
12.Concentrated HBr is 48.0% HBr by mass and has a density of 1.50 g/mL. How many grams of this solution are required to prepare 500.0 mL of a 0.600 M HBr solution? (Ar: H = 1, Br = 80).
a)24.3
b)40.2
c)50.6
d)45.4
e)54.6
13.A concentrated solution of AgNO3 is 21.9% by weight and the density is 1.220 g/cm3. How many milliliters of the solution are required to prepare 150.0 mL of a 0.200M solution? (Ar: Ag = 108, N = 14, O = 16).
a)18.1
b)17.3
c)19.7
d)20.6
e)19.1
14.A concentrated solution of (NH4)2SO4 is 36.0% by weight and the density is 1.2077 g/cm3. How milliliters grams of the solution are required to prepare 175.0 mL of a 0.120M solution? (Ar: N = 14, S = 32, O = 16, H = 1)
a)7.71
b)5.93
c)6.92
d)8.26
e)6.40
15.Concentrated HI is 47.0% HI by mass and has a density of 1.50 g/mL. How many milliliters of this solution are required to prepare 250.0 mL of a 1.50 M HI solution? (Ar: H = 1, I = 127).
a)66.4
b)102
c)62.3
d)48.0
e)68.0
16.A 25.0 mL sample of concentrated HCl (12.0 M) is diluted to a final volume of 750.0 mL. What is the molarity of the final solution? (Ar: H = 1, Cl = 35.5).
a)0.400
b)0.800
c)0.500
d)1.00
e)0.600
17.A 10.0 mL sample of concentrated HNO3 (15.8 M) is diluted to a final volume of 500.0 mL. What is the molarity of the final solution? (Ar: H = 1, N = 14, O = 16).
a)0.316
b)0.500
c)0.250
d)0.450
e)0.375
18.A 25.0 mL sample of concentrated H3PO4 (14.7 M) is diluted to a final volume of 500.0 mL. What is the molarity of the final solution? (Ar: H = 1, P = 31, O = 16).
a)0.735
b)0.765
c)0.670
d)0.795
e)0.700
19.Fluoxymesterone, C20H29FO3, is an anabolic steroid. A solution is prepared by dissolving 10.0 mg of the steroid in 500.0 microL of water. A 100.0 mL portion of this solution is diluted to a final volume of 100.0 mL. What is the resulting molarity? (Ar: C = 12, O = 16, F = 19, H = 1).
a)5.94 x 10-11
b)1.19 x 10-10
c)5.94 x 10-8
d)2.38 x 10-11
e)1.19 x 10-7
20.A solution containing Mn2+ is prepared by dissolving 1.485 g of pure manganese in nitric acid and diluting to 1.00 L. A 10.00 mL aliquot is then diluted to 500.0 mL. What is the molarity of the final solution? (Ar: Mn = 55).
a)5.06 x 10-3
b)0.0506
c)0.0253
d)5.41 x 10-4
e)2.53 x 10-4
21.A solution is prepared by dissolving 516.5 mg of oxalic acid (C2H2O4) to make 100.0 mL of solution. A 10.00 mL portion is then diluted to 250.0 mL. What is the molarity of the final solution? (Ar: C = 12, H = 1, O = 16).
a)5.737 x 10-2
b)5.737
c)2.295
d)2.295 x 10-3
e)5.738 x 10-2
22.A 10.0 mL sample of concentrated HF (16.5 M) is diluted to a final volume of 250.0 mL. What is the molarity of the final solution? (Ar: H = 1, F = 19).
a)0.570
b)0.630
c)0.690
d)0.660
e)0.600
23.What volume (mL) of 0.872 M K2CrO4 should be used to prepare 100.0 mL of a 0.125 M solution? (Ar: K = 39, Cr = 52, O = 16).
a)13.9
b)14.3
c)13.5
d)14.9
e)14.8
24.What volume (mL) of 1.57 M AgNO3 should be used to prepare 250.0 mL of a 0.200 M solution? (Ar: Ag = 108, N = 14, O = 16).
a)29.3
b)31.8
c)30.2
d)33.8
e)32.7
25.What volume (mL) of concentrated H3PO4 (14.7 M) should be used to prepare 125 mL of a 3.00 M H3PO4 solution? (Ar: H = 1, P = 31, O = 16).
a)20.0
b)25.5
c)27.5
d)22.5
e)17.5
26.A 50.0 mL sample of a 37.0% HCl solution has a density of 1.19 g/mL. The sample is diluted to a volume of 0.400 L. What is the molarity of the final solution? (Ar: H = 1, Cl = 35.5).
a)1.68
b)1.87
c)1.51
d)4.08
e)1.79
27.A 14.3 mL sample of a 15.0% solution of K2CrO4 has a density of 1.129 g/cm3. The sample is diluted to a volume of 100.0 mL What is the molarity of the final solution? (Ar: K = 39, Cr = 52, O = 16).
a)0.150
b)0.200
c)0.125
d)0.225
e)0.175
28.A 31.8 mL sample of a 21.9% solution of AgNO3 has a density of 1.220 g/cm3. The sample is diluted to a volume of 250.0 mL What is the molarity of the final solution? (Ar: Ag = 108, N = 14, O = 16).
a)0.275
b)0.225
c)0.200
d)0.175
e)0.250