Gas Practice Problems  1. A sample of a gas has a volume of 300.0 ml at 546 oC and a pressure of 940. mm Hg. What volume would this gas occupy at STP?

P1V1 = P2V2 (940 mm Hg)(300.0 ml) = (760 mm Hg) V2 T1 T2 819 K273 K  

V2 = 124 ml 

2. A weather balloon contains 5.8 liters of helium when released at a pressure of 750 mm Hg and a temperature of 5 oC. At a higher altitude the pressure is 0.50 atmospheres and the volume becomes 9.6 liters. What is the temperature in degrees centigrade at the higher altitude?

(5.8 L)(750 mm Hg) = (9.6 L)(380 mm Hg)(278 K) T2

T2 = 233 K (230)

(233 K – 273) = -40oC

3. A balloon may withstand a maximum pressure of 1.5 atmospheres. Nitrogen gas is put into it at a pressure of 730 mm Hg. What additional pressure of oxygen could be put into the balloon?

1.5 atm (760 mm Hg / atm) = 1140 mmHg 1140 mm Hg – 730 mm Hg = 410 mm Hg

4. A sample of a gas has a volume of 300. ml at 546 oC and a pressure of 0.62 atmospheres. What is the volume at STP?

(0.62 atm)(300. ml) = (1 atm) V2 V2 = 62 ml

819 K 273 K

5. A gas has a volume to 5.72 liters at STP. If the volume changes to 4.76 liters and the pressure to 934 mm Hg, what will be the temperature of the gas in degrees centigrade? 

(760 mm Hg)(5.72 L) = (934 mm Hg)(4.76 L)

273 K T2 

T2 = 279 K

(279 K -273 ) = 6 oC

6. A 500 ml flask contains argon and chlorine gas under 2.000 atmospheres pressure. The pressure of the argon is 912 mmHg. What is the pressure of the chlorine gas?

 2 atm (760 mm Hg / 1atm) = 1520 mmHg 1520 mm Hg – 912 mm Hg = 608 mm Hg