General Chemistry I
CHEM 1311.003
Exam 2




1. A compound containing only nitrogen and oxygen is 63.65% nitrogen by mass, and the remainder of the mass is due to oxygen. What is the empirical formula of this compound?

a) N2Ob) NOc) NO2d) NO3e) N2O5
2. Oxygen reacts with nitrogen monoxide to form nitrogen dioxide. The chemical equation for the reaction is

2NO(g)         +         O2(g)         ---------->         2NO2(g)

If 18.784 g NO and 13.215 g O2 are present in a closed tank and they react as described by the equation above, what is the limiting reactant (also called limiting reagent) and what mass of nitrogen dioxide will be formed?

a) NO is the limiting reagent and 11.185 g NO2 will be formed.
b) NO is the limiting reagent and 15.973 g NO2 will be formed.
c) NO is the limiting reagent and 28.800 g NO2 will be formed.
d) O2 is the limiting reagent and 15.973 g NO2 will be formed.
e) O2 is the limiting reagent and 28.800 g NO2 will be formed.

3. A sample of a gas is confined in a cylinder under a pressure of 3.182 atm at a temperature of 15.11 C. Initially, the volume of the gas is 9.162 L. If the pressure on the gas is increased to 6.741 atm and the temperature does not change, what will the new volume of the gas be?
a) 2.181 Lb) 4.325 L c) 6.199 L
d) 7.244 Le) 8.917 L
4 What pressure would be exerted by 7.144 g SO2 gas when it is confined to a 2.15 L container at 31.22 C?

a) 5.21 atmb) 3.87 atmc) 2.45 atm
d) 1.30 atme) 0.55 atm
5. What is the density of O2 gas when the pressure is 5.187 atm and the temperature is 13.73 C?
a) 1.117 g / Lb) 3.500 g / Lc) 4.992 g / L
d) 6.105 g / Le) 7.051 g / L
6. Balance the equation

C3H8         +       O2         ---------->         CO2         +         H2O

If your set of coefficients happens to have a common factor other than one, divide all coefficients by the greatest common factor to get the chemical equation in lowest terms. When the equation is balanced using integers in lowest terms, the coefficient of O2 is
a) 1b) 2c) 3d) 4e) 5
7. The reaction

CaCl2(aq)         +         Na2CO3(aq)         ----------> CaCO3(s)         +         2NaCl(aq)

is an example of what kind of reaction?
a) metathesisb) displacementc) decomposition
d) combinatione) combustion
8. Which of the following compounds is insoluble in water?
a) Pb(NO3)2b) Ba(C2H3O2)2c) CaCl2
d) AgCle) NaBr
9. A precipitate will be formed when an aqueous solution of ammonium chloride is added to an aqueous solution of
a) sodium phosphateb) silver(I) nitrate
c) potassium carbonated) calcium nitrate
e) sodium acetate
10. When solutions of calcium chloride and potassium sulfate are mixed, the spectator ions in the resulting reaction are
a) Only K+b) Only SO42-
c) Ca2+ and SO42-d) K+ and Cl-
e) K+ , Ca2+ , Cl- , and SO42-
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Last modified: Thursday June 18, 1998