Question

****Temperature must be in Kelvins in all Gas Law Calculations *****
Boyle’s Law

1)   Ammonia gas occupies a volume of 450 mL at a pressure of 90 kPa. What volume will it occupy at standard pressure?

2)   A sample of fluorine gas exerts a pressure of 900 mmHg. When the pressure is changed to 1140 mmHg, the volume is 250 mL. What was the original volume?

Charles’ Law
Use Charles’ Law to answer the following questions. Show all of your work and units.

3) A sample of nitrogen occupies a volume of 250 mL at 25oC. What volume will it occupy at 95oC?

4) Fluorine gas at 300 K occupies a volume of 0.500 L. To what temperature should it be lowered to
      bring the volume down to 0.300 L?

Combined Gas Law
Use the Combined Gas Law to answer the following questions. Show all of your work and units

5). A balloon is filled with 6.5 L of helium gas at 25oC and 1.0 atm. What volume will the balloon
     have when the temperature is lowered to -25oC and the pressure is increased to 1.5 atm?

6) A sample of carbon dioxide occupies 200 L at 22oC and 1.0 atm. At what temperature will it
     expand to 1000 L at 0.90 atm?

Answer 1

Boyle law

for a fixed mass, at constant temperature the absolute pressure is inversely proportional to the volume of a gas.

Ans 1

Volume V1 = 450 mL

Pressure P1 = 90 kPa

Standard pressure P2 = 1 atm

Volume V2 =?

P1/P2 = V2/V1

V2 = P1V1/P2

= 90*450/1 = 40500 mL x 1L/1000 mL

V2 = 40.5 L

Ans 2

Pressure P1 = 900 mmHg

pressure P2 = 1140 mmHg

volume V2 = 250 mL

Original volume V1 =?

V1 = P2V2/P1

= 1140*250/900 = 316.67 mL

Charles law

for a fixed mass, at constant pressure the volume of a gas is directly proportional to the absolute temperature.

Ans 3

volume V1 = 250 mL

Temperature T1 = 25 + 273 = 298 K

Temperature T2 = 95 + 273 = 368 K

V1/T1 = V2/T2

250/298 = V2/368

V2 = 308.72 mL

Ans 4

Temperature T1 = 300 K

volume V1 = 0.500 L

Volume V2 = 0.300 L

T2 =?

V1/T1 = V2/T2

0.500/300 = 0.300/T2

T2 = 180 K