CHEM 1411-Home-work 3B
1) Given:
2 Na + O2  Na2O2
Calculate the moles of sodium peroxide (Na2O2) produced if 32.5 g of sodium reacts with excess
oxygen:
A) 1.41 mol
B) 0.707 mol
C) 0.354 mol
D) 55.1 mol
E) 27.6 mol
2) The “set-up” which follows for the problem “How many grams of SO 2 will be produced from 10.0 g of
S8 and an excess of O2” according to the reaction is correct except the letters A and B have replaced
the numbers in one of the conversion factors. What are the numerical values of A and B, respectively?
S8  8 O2  8 SO2
10.0 g S8 
A) 8 and 8
1 mole S8
A moles SO2 64.07 g SO2


256.56 g S8
B moles S8
1 mole SO2
B) 1 and 8
C) 8 and 1
D) 1 and 1
3) In the following reaction, how many grams of H2O are produced if 3.65 g of N2H4 react?
N2H4  3 O2  2NO2  2H2O
A) 0.625 g B) 1.47 g
C) 10.5 g
D) 11.2 g
E) 4.10 g
4) For the reaction: 2 P + 3 Cl2  2 PCl3 if 32.5 g of Cl2 reacts completely with excess P, how many
grams of PCl3 will be produced?
A) 42.0 g
B) 62.9 g
C) 83.9 g
D) 94.4 g
5) How many moles of H2O will be produced if 6.80  1024 formula units of NH4NO3 are decomposed in
the reaction given below? NH4NO3  N2O  2H2O
A) 0.876 mole
B) 3.30 moles
C) 5.40 moles
D) 22.6 moles
E) 25.6 moles
6) Propane (C3H8) burns in oxygen to form CO2 and H2O according to the following equation. How many
grams of O2 are required to burn 3.01  1023 propane molecules?
C3H8  5 O2  3 CO2  4 H2O
A) 80.0 g
B) 40.0 g
C) 160. g
D) 16.0 g
E) 64.0 g
7) If 5.0 grams of CO and 5.0 grams of O2 are combined according to the following equation:
2 CO + O2  2 CO2, which is the limiting reagent?
A) CO2
B) CO
C) O2
D) neither CO or O2
8) 15.0 g of Cu are combined with 46.0 g of HNO 3 (molar mass  63.02), according to the reaction
3Cu  8HNO3  3Cu(NO3)2  2NO  4H2
Which reactant is limiting, and how many grams of H 2 is produced?
A) Cu, 3.79 g
B) Cu, 0.636 g
C) HNO3, 0.737 g
D) HNO3, 6.13 g
E) HNO3, 0.981 g
9) In a certain experiment using Ca and an excess of F, 10.6 g of CaF2 is obtained. This represents a 76.4
percent yield. What is the theoretical yield of ZnS for this experiment?
A) 139 g
B) 126 g
C) 141 g
D) 157 g
E) 133 g
10) In the atmosphere, the air pollutant nitrogen dioxide (NO2) reacts with water to produce nitric acid
(HNO3), a component of acid rain. The reaction for the formation of nitric acid is:
3 NO2(g)  H2O( )  2 HNO3(aq)  NO(g)
If 8.50 moles of nitrogen dioxide reacts with excess water, what is the actual yield (in grams) of
NO if the percent yield is 89.4%?
A) 57.8 g
B) 136 g
C) 85.0 g
D) 76.0 g
E) 36.1 g