Practice Problems
Molar Mass and Density
1) What is the molar mass of an unknown gas which has a density of 1.03 g/L, at a pressure of 80.0 kPa and
a temperature of 25C?
2) Determine the density of carbon tetrachloride gas at 700. torr and 25 C.
Gas Stoich
1) How many liters of CO2 would be collected over water from the combustion of 35.0 grams of
cyclohexane, if the gas is collected at a barometric pressure of 765 mmHg and a temperature 30.C?
Graham’s Law
1) What is the ratio of the rates of effusion (or diffusion) for nitrogen gas and to chlorine gas?
2) If it takes 2.5 hr for 2.0 L of CO2 gas to effuse, then what is the molar mass of a gas which requires 32
minutes for 2.0 L to effuse through the same opening? What is the gas?
3) How long will it take for 2.0 L of Kr gas to effuse through the same opening?
4) The rate of effusion of CO2 is 0.80 L/hr and the rate of effusion of gas X is 3.75 L/hr. What is molar mass
and identity of X?
5) A sample of N2 gas effuses 1.8 times faster than some unknown gas. What is the molar mass of the
unknown gas?