Page 196 - Theory and Problems of BEGINNING CHEMISTRY

CHAP. 12] GASES 185

Solved Problems

INTRODUCTION
12.1. What is the difference between gas and gasoline?
Ans. Gas is a state of matter. Gasoline is a liquid, used mainly for fuel, with a nickname gas. Do not confuse the
two. This chapter is about the gas phase, not about liquid gasoline.

12.2. What is a fluid?
Ans. A gas or a liquid.

PRESSURE OF GASES
12.3. Change 806 mmHg to (a) torr, (b) atmospheres, and (c) kilopascals.

1 atm 101.3kPa
Ans. (a) 806 torr (b) 806 torr = 1.06 atm (c) 1.06 atm = 107 kPa
760 torr 1 atm
12.4. Change (a) 703 torr to atmospheres, (b) 1.25 atm to torr, (c) 743 mmHg to torr, and (d) 1.01 atm to
millimeters of mercury (mmHg).

1 atm 1 torr

Ans. (a) 703 torr = 0.925 atm (c) 743 mmHg = 743 torr
760 torr 1 mmHg

760 torr 760 mmHg
(b)1.25 atm = 950 torr (d)1.01 atm = 768 mmHg
1 atm 1 atm
12.5. How many pounds force does 1 atm pressure exert on the side of a metal can that measures 6.0 in. by
2
9.0 in.? (1 atm = 14.7 lb/in. )
Ans. Area = 6.0in. × 9.0in. = 54 in. 2

14.7lb
2
54 in. 2 = 790 lb = 7.9 × 10 lb
1in. 2
BOYLE’SLAW
12.6. What law may be stated qualitatively as “When you squeeze a gas, it gets smaller”?
Ans. Boyle’slaw

12.7. Calculate the product of the pressure and volume for each point in Table 12-1. What can you conclude?
Ans. PV = 8.0L·atm in each case. You can conclude that PV is a constant for this sample of gas and that Boyle’s
law is obeyed.

12.8. If 4.00 L of gas at 1.22 atm is changed to 876 torr at constant temperature, what is its final volume?

760 torr
Ans. 1.22 atm = 927 torr
1 atm
P 1 V 1 = P 2 V 2
(927 torr)(4.00 L)
P 1 V 1
V 2 = = = 4.23 L
P 2 876 torr
12.9. If 1.25 L of gas at 780 torr is changed to 965 mL at constant temperature, what is its final pressure?
(780 torr)(1250 mL)
P 1 V 1
Ans. P 2 = = = 1010 torr
V 2 965 mL