Problem Set 6a
Chem 141
Required Problems: (turn these in)
1. Sodium azide (NaN3) is the primary chemical substance used in automobile air bags. Upon impact, the decomposition of
sodium azide is initiated to produce sodium metal and nitrogen gas which then inflates the bag. How many liters of
nitrogen gas are produced at 1.15 atm and 30.0C when 145.0 grams of sodium azide decomposes?
2. Calcium carbonate (such as that in limestone) reacts with aqueous hydrochloric acid to produce carbon dioxide, aqueous
calcium chloride and water. How many liters of carbon dioxide are produced at 20C and 745 torr when 3.583 grams of
calcium carbonate is dissolved in solution containing 1.550 grams of hydrochloric acid?
over
Chem 141, Dr. Haefner
3. Titanium(III) chloride can be used to catalyze the polymerization of ethylene. It is prepared by hydrogen reduction of
Titanium(IV) chloride. Reaction of hydrogen gas with titanium(IV) chloride gas produces solid titanium(III) chloride and
hydrogen chloride gas.
(a) Write a BALANCED chemical reaction for the preparation of titanium(III) chloride
(b) A 250 L reaction vessel at 325C is filled with hydrogen gas to a pressure of 1.3 atm. Titanium(IV) chloride is then added
to bring the total pressure to 3.00 atm. How many grams of titanium(III) chloride will be produced after completion of the
reaction?
(c) What will be the pressure of the resulting hydrogen chloride gas that is also produced?
over
Chem 141, Dr. Haefner
4. Nitrogen gas is commonly sold in 49.0 L steal cylinders at a pressure of 150 atm.
(a) How many moles of nitrogen are in the container if the temperature of the cylinder is 21C.
(b) How many moles of nitrogen will there be if the container above is heated to 100C? (careful here)
(c) What is the mass of nitrogen gas in the cylinder in part (a)?
(d) What volume would the nitrogen occupy at 21C, if the pressure was reduced to 1.02 atm?
(e) What would be the pressure of the nitrogen gas in the cylinder when the temperature is raised to 39C?
over
Chem 141, Dr. Haefner
5.
An unlabeled gas cylinder was recently found in the laboratory. A sample of the gas was removed and analyzed.
A 500.0 mL sample of the gas at 15C and a pressure of 736 mmHg was found to weigh 2.688 g. Determine the molar
mass of the gas. What element is the gas?
6. A 0.4550 g sample of an unknown organic compound with the empirical formula CH2O was placed into a 150.0 ml vessel
and was vaporized into a gas. At 175.0C, the pressure of the vaporized compound was measured at 941.1 torr.
(a) Determine the molar mass of the compound
(b) Determine the molecular formula of the compound.
over