NAME:
PERIOD:
CHAPTER FIVE HOMEWORK
1. Read pp. 187 - 229.
2. Solve the following problems
1. Freon-12 (CF2Cl2) had been commonly used as the refrigerant in central home air
conditioners. The system was initially charged to a pressure of 4.80 atm. Express this pressure in
each of the following units (1 atm = 14.7 psi).
(a) mm Hg
(b) torr
(c) kPa
(d) psi
2. An aerosol can contains 400.0 mL of compressed gas at 5.20 atm pressure. When all the gas is
sprayed into a large plastic bag, the bag inflates to a volume of 2.14 L. Determine the pressure of
the gas inside the bag. Assume temperature is constant.
3. If 0.500 mol of nitrogen gas occupies a volume of 11.2 L at 0.00C, what volume will 2.00 mol
of nitrogen gas occupy at the same temperature and pressure?
OVER
4. Complete the following table for an ideal gas:
P (atm)
V (L)
7.74 x 103 Pa
12.2 mL
43.0 mL
455 torr
745 mm Hg
11.2 L
n (mol)
T
25.00C
0.421 mol
223 K
4.4 x 10-2 mol
3310C
0.401 mol
5. The steel reaction vessel of a bomb calorimeter, which has a volume of 75.0 mL, is charged
with oxygen gas to a pressure of 145 atm at 22.00C. Calculate the number of moles of oxygen in
the reaction vessel.
6. A balloon has a volume of 175.0 cm3 at 19.00C. At what temperature, in degrees Celsius, will
the volume of the balloon have increased by 25.0% (at constant pressure)?
7. A container is filled with an ideal gas to a pressure of 40.0 atm at 0.000C. At what
temperature will the pressure be 25.0 atm?
8. An ideal gas is contained in a cylinder with a volume of 500.0 mL at a temperature of 30.00C
and a pressure of 710.0 torr. The gas is then compressed to a volume of 25.0 mL, and the
temperature is raised to 820.00C. What is the new pressure of the gas?
9. What mass of helium is required to fill a 1.50 L balloon at STP?
10. A student adds 4.00 g of dry ice (solid CO2) to an empty balloon. What will be the volume
of the balloon at STP after all the dry ice sublimes?
OVER
11. A particular balloon is designed by its manufacturer to be inflated to a volume of no more
than 2.50 L. If the balloon is filled with 2.00 L of helium at sea level, is released, and rises to an
altitude at which the atmospheric pressure is only 500 mm Hg, will the balloon burst? (Assume
temperature is constant).
12. Nitrogen oxide is a pollutant commonly found in smokestack emissions. One way to remove
it is to react it with ammonia.
4 NH3 (g) + 6 NO (g) → 5 N2 (g) + 6 H2O (l)
How many liters of ammonia are required to change 12.8 L of nitrogen oxide into nitrogen gas?
Assume 100% yield and that all the gases are measured are at the same temperature and pressure.
13. Calculate the volume of O2, at STP, required for the complete combustion of 125.0g of
octane (C8H18) to CO2 and H2O.
14. Nitric acid can be prepared by bubbling dinitrogen pentoxide into water:
N2O5 (g) + H2O (l) → 2 H+ (aq) + 2 NO3- (aq)
(a). How many moles of H+ are obtained when 1.50 L of N2O5 at 25.00C and 1.00 atm are
bubbled into water?
(b). The solution obtained in (a) after the reaction is complete has a volume of 437 mL. What is
the molarity of the nitric acid obtained?
15. Ammonium nitrate can be used as an effective explosive because it decomposes into a large
number of gaseous products. At a sufficiently high temperature, ammonium nitrate decomposes
into nitrogen, oxygen, and steam.
(a). Write a balanced equation for the decomposition of ammonium nitrate.
(b). If 1.00 kg of ammonium nitrate is sealed into a 50.0 L steel drum and heated to 7870C, what
is the pressure in the drum, assuming 100% decomposition?
OVER
16. A student prepares a sample of hydrogen gas by electrolyzing water at 25.00C. She collects
152 mL of H2 at a total pressure of 758 mm Hg.
(a). If the vapor pressure of water at 25.00C is 23.76 mm Hg, calculate the partial pressure of the
H2 gas.
(b). Calculate the mass, in grams, of H2 collected.
17. A sample of gas collected over water at 42.00C occupies a volume of 1.00 L. The wet gas
has a pressure of 0.986 atm. The gas is dried and the dry gas occupies a volume of
1.04 L with a pressure of 1.00 atm at 90.00C. Using this information, calculate the vapor pressure
of water at 42.00C.
18. Nitrogen can react with steam to form ammonia and nitrogen monoxide gases.
A 20.0 L sample of nitrogen at 1730C and 772 mm Hg is made to react with excess steam. The
products are collected at room temperature (25.00C) into an evacuated flask with a volume of
15.0 L.
(a). Write a balanced equation for the reaction.
(b). What is the total pressure of the products in the collecting flask after the reaction is complete?
(c). What is the partial pressure of each of the products in the flask?
19. A gas consisting of only carbon and hydrogen has an empirical formula of CH2. The gas has
a density of 1.65 g/L at 267.00C and 734 torr. Determine the molar mass and molecular formula
of the gas.
OVER
20. Helium filled balloons rise in the air because the density of helium is less than the density of
air.
(a). If air has an average molar mass of 29.0 g/mol, what is the density of air at 25.00C and 755
mm Hg?
(b). What is the density of helium at the same temperature and pressure?
(c). Would a balloon filled with carbon dioxide at the same temperature and pressure rise?
21. Phosgene is a highly toxic gas made up of carbon, oxygen, and chlorine atoms. Its density at
1.05 atm and 25.00C is 4.24 g/L.
(a). What is the molar mass of phosgene?
(b). Phosgene is made up of 12.1% C, 16.2% O, and 71.7% Cl. What is the molecular formula of
phosgene?
22. Calculate the average kinetic energy of oxygen molecules in a sample of oxygen at 300.00C.
23. Calculate the root mean square speed of CO2 gas molecules at 450.0 K.
24. Do all the molecules in a one mole sample of C2H6 (g) have the same energy
at 273 K? Explain.
25. Do all the molecules in a one mole sample of NH3 (g) have the same velocity
at 347 K? Explain.
26. Calculate the rate of effusion of PH3 molecules through a small opening if NH3 molecules
pass through the same opening at a rate of 8.02 mL/s. Assume the same temperature and equal
partial pressures of the two gases.
OVER
27. How many times faster than He would NO2 gas effuse?
28. Calculate the pressure exerted by 0.3000 mol of He in a 0.2000 L container
at -25.00C.
(a). Using the ideal gas equation.
(b) Using van der Waal’s equation.
a = 0.034 atm∙L2/ mol2
b = 0.0237 L∙mol
29. Calculate the pressure exerted by 85.0 moles of Cl2 gas in a 20.0 L container at 25.00C using
the van der Waal’s equation.
a = 6.49 atm∙L2/mol2
b = 0.0562 L∙mol
OVER