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