Question

(a) A piston at 1.5 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 0.17 L?
______atm

(b) A piston at 120.0°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 4.8 L at constant pressure?
_______ °C

(c) A piston at 4145 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 1.04 L?
______ atm

Answer 1

We use PV = nRT formula

1) at constant temp and with no gas added or removed we have PV = constant , hence P1V2 = P2V2

P1 = 1.5 atm , V1 = 3.5 L , V2 = 0.17 L we find P2

1.5 x 3.5 = P2 x 0.17

P2 = 30.88 atm

b) at constant P we have V = constantx T , hence V2/V1 = T2/T1

T1= 120C = 120+273.15 K = 393.15 K , V1= 2.5 L , V2 = 4.8 L , T2 = ?

4.8 /2.5 = T2/393.15

T2 = 754.9 K = 754.9-273.15 C = 481.7 C

c) P1 = 4145 torr = 4145 /760 atm = 5.454 atm ( 1 atm = 760 torr) , V1 = 4.7 L , V2 = 1.04 L , P2 = ?

5.454 x 4.7 = P2 x 1.04

P2 = 24.65 tm