The temperature of 360 mL of a gas is decreased from 20°C to -40°C while the pressure is held constant What is the new volume of the gas?
A
180 mL
B.
286 ml
C453 mL
D.
720 ml

The answer is: B. 286 mL

Explanation:

Given:

V₁ = 360 mL = 0.36 L

T₁ = 20°C = 293 K

T₂ = -40°C = 233 K

Constant pressure

Question: What is the new volume of the gas, V₂ = ?

The relation between the temperature and the volume at constant pressure is known like the Charles's law

286.3 mL

Explanation:

The question specifies that pressure was held constant, this immediately reminds us of Charles law. The volume of a given mass of has is directly proportional to its temperature at constant pressure.

From

V1/T1 = V2/T2

V1= initial volume = 360 ml

T1 = initial temperature= 20°C +273= 293K

T2= final temperature= -40°C + 273= 233K

V2= final volume =

V2= V1T2/T1

V2= 360 × 233/ 293

V2= 286.3 mL