Question

(a) A piston at 4.9 atm contains a gas that occupies a volume of 3.5 L. What pressure would have to be placed on the piston to force the volume to adjust to 1.3 L?

_____atm

(b) A piston at -57.0°C contains a gas that occupies a volume of 2.5 L. To what temperature would the gas have to be heated to increase the volume to 5.4 L at constant pressure?

_____°C

(c) A piston at 145 torr contains a gas that occupies a volume of 4.7 L. What pressure would have to be placed on the piston to force the volume to adjust to 1.08 L?

______atm

Answer 1

According to ideal gas equation, PV = n*RT

(a)

Keeping the temperature constant, we have :

P1V1 = P2V2

Putting values we get :
4.9*3.5 = P₂*1.3

Thus, P₂ = 13.19 atm

Thus, extra pressure required = 13.19-4.9 = 8.29 atm

(b)

Keeping the pressure constant, we have :

V1/T1 = V2/T2

T1 = -57 C = -57+273 = 216 K

Putting values we get :
2.5/216 = 5.4/T2

Thus, T₂ = 466.56 K = 193.56 C

(c)

Keeping the temperature constant, we have :

P1V1 = P2V2

Putting values we get :
145*4.7 = P₂*1.08

Thus, P₂ = 631 torr

Thus, extra pressure required = 631-145 = 486 torr