Used to make the ws on Additional problems in 2011
Name ______________
Molecular Composition of Gases
I.
Gas density
1.
2.
3.
4.
5.
Calculate the density of sulfur dioxide at STP to 3 sig. Figs. Ans. 2.87 g/L
What is the density of hydrogen sulfide gas at STP?(3sf) Ans. 1.52 g/L
Determine the mass of 30.0ml of nitrogen at STP? Ans..0375g
What is the mass of 1.00L of carbon dioxide at STP? Ans. 1.96 g
At standard conditions, 225 ml of a gas has a mass of 0.6428 g.
a) Calculate the density of this gas? Ans. 2.87g/L
b) Determine the molecular weight of this gas? Ans. 64 g/mol
6. What is the density of dinitrogen monoxide at STP?
1.96 g/L
7. What is the volume of 1.25g of methane C4H10, at STP? .483 L
8. 7.52g of chlorine will occupy a volume of __________ at STP?
2.37 L
9. Determine the volume of 754mL of sulfur trioxide at STP?
2.64 g
10. If the mass of 250mL of a gas at STP is 0.179g, what is the molecular
weight of this gas?
16.0g/mol
II.
Ideal Gas Law
1. Derive the value of “R” the universal gas law constant in (L mmHg./mol. K).
Ans. 62.4L mmHg/mol K
2. For an ideal gas, calculate:
a) The volume occupied by 0.105 moles at –230C and 5.00 atm. Ans 0.040 L
b) The number of moles of gas in a 500mL container at 270C and 725 Torr.
Ans. 0.019 mol
c) The Celsius Temperature at which 0.671 moles occupies 25.0 L at a
pressure of 2.45 atm. Ans. 8390C
d) The pressure exerted by 5.27 x 10-2 moles of a gas in a 1.53 mL container
at –230C. Ans. 7.07 atm
3. Calculate the density of a gas at 270C and 0.870atm if its molecular weight
is 34.1g/mol. Ans 1.21g/L
4. What is the density of carbon dioxide at 745 mmHg and –5.00C?
Ans. 1.96 g/L
5. .Determine the molecular weight of a gas whose density is 1.84 g/L at 520C
and 600Torr. Ans 62.2g/mol
Volume-Volume
1. In the electrolysis of water, 75.0mL of oxygen are produced. How many
milliliters of hydrogen are produced?
Ans. 150. mL
2. How many liters of hydrogen are required to react with excess nitrogen to
produce 50.0L of ammonia (NH3)? Ans. 75.0 L
3. Ammonia burns in oxygen to give nitrogen monoxide (N O) and water. If
20.0L of ammonia are burned, how many liters of oxygen are required?
Ans. 25.0 L
4. Carbon monoxide burns in oxygen and forms carbon dioxide.
a) How many liters of carbon dioxide are produced from 15.0 L of CO?
Ans. 15.0 L
b) How many liters of oxygen are needed? Ans.
7.5 L
5. Acetylene gas, C2H2, burns in air to produce CO2 (q) and H2O(q). What volume
of oxygen is needed to burn 25.0L of acetylene? Ans. 62.5 L
6. If 120mL of ethane gas, C2H6, burns to produced carbon dioxide and water
vapor, what volume of carbon dioxide is formed? Ans. 240.0 ml
7. If 400.0 ml of hydrogen and 400.0 ml of oxygen are mixed and ignited, what
volume of oxygen remains uncombined? Ans. 200.0 ml
III. Mass – Volume
1. How many grams of sodium are needed to release 4.0L of hydrogen from
water? Ans. 8.21 g
2. When 130.0 g of zinc reacts with excess hydrochloric acid, what volume of
hydrogen is produced?
Ans. 44.8 L
3. How many liters of oxygen can be produced by the decomposition of 90.0g of
water? Ans. 56.0 L
4. How many liters of hydrogen would be produced in question #3? Ans. 112 L
5. In the reaction between aluminum and oxygen, what mass of aluminum is
need to react with 500.0 L of oxygen? Ans. 804 g
6. What volume of oxygen is produced by the decomposition of 2.85 g of
potassium chlorate? Ans. 0.782 L
7. If excess chlorine reacts with a solution containing 20.0g of potassium
bromide, what volume of bromine gas is formed? Ans. 1.90 L
8. What mass of magnesium will react with excess sulfuric acid to produce
500ml of hydrogen? Ans. 0.534g