Problem set 9
Gases, Liquids, and Solids
1. If the temperature of a gas sample is doubled in a constant pressure, what will happen to the
volume?
2. A constant volume of oxygen gas is heated from 120°C to 212°C. The final pressure is 20.3
atm. What is the initial pressure?
3. An unknown amount of He gas occupies 3001 mL at 2.00 atm. Pressure and 75°F. What is
the weight of the gas in the container? (R = 0.0821 L.atm/mol.K)
4. If there is 5.3g of CO2 gas in a 2600mL cylinder at 25C, what is the gas pressure within
the cylinder?
5. Calculate the molecular weight of a gas if 3.30g of the gas occupies 660 mL at 735 mm Hg
and 27C.
6. The three main components of dry air and the percentage of two of each are nitrogen
78.08%. oxygen 20.95%, and argon 0.93%. Calculate the partial pressure of each gas in a
sample of dry air at 760 mm Hg.
Dr. Behrang Madani
Chemistry 100
IVC
7. We mix 16 L of nitrogen gas at 27C and 1.0 atm with 52 L of neon gas at 27C and 1.0
atm in a 6.0 L tank. Calculate the partial pressure of each gas and total pressure in the tank at
27C.
8. Consider the following reaction: 2H2O2(aq) → 2H2O(g) + O2(g). Suppose 430 mL of
oxygen is collected at 32C and has a total pressure of 1.056 atm by this process. What is the
partial pressure of oxygen gas in the sample? How many moles of oxygen gas are present in
the sample? How many grams of H2O2 must have reacted to produce this quantity of oxygen?
(vapor pressure of water is 35.663 mm Hg at 32C).
9. A gaseous mixture contains 12.1 g of N2 and 4.05 g of He. What is the volume of this
mixture at STP?
10. Chloroform (CHCl3) can be produced by reaction CH4(g) + 3Cl2(g) → CHCl3(l) +
3HCl(g). In one experiment 25g of CH4 were used. Calculate the volume of HCl produced at
1.0 atm and 27C.
11. Arrange these compounds in each set in order of increasing the boiling point:
a) CH3-CH2-CH2-CH2-CH3
CH3-CH2-CH3
CH3-CH2-CH2-CH3
CH3
b) CH3-CH2-CH3
CH3-CH2-CH2-CH2-CH3
CH3-C-CH2-CH3
CH3
Dr. Behrang Madani
Chemistry 100
IVC
c) Mg(OH)2, CCl4, NH3, CH2Cl2
d) KOH, CO, He, H2O
12. By using the pressure cooker, is the boiling point changed? How? Why?
13. Which substance in each pair has the largest vapor pressure at a given temperature?
a) CO or CO2
b) H2O or HCl
c) CH4 or CH3OH
14. The molar heat of fusion of sodium metal is 2.60 kJ/mol, whereas its heat of vaporization
is 97.0 kJ/mol. What quantity of heat would be needed to melt 1.50 g of sodium at its normal
melting point? What quantity of heat would be needed to vaporize 2.6 g of sodium at its
normal boiling point?
Dr. Behrang Madani
Chemistry 100
IVC