Question

NUMERICAL PROBLEMS ON CHARLES' LAW
: 279 cm of gas at 87 °C is cooled to standard temperature, at constant pressure. Calculate
the volume of gas at standard temperature.​

Answer 1

Answer:

PV=nRT

V∝T

VT

′

=V

′

T at constant pressure for a fixed amount of gas.

Initial volume V = 300 ml.

Initial temperature T = 27

o

C =27+273 K = 300 K

Final volume V' = ??.

Final temperature T' =− 8

o

C =273−8 K = 265 K.

300 mL× 265 K =V

′

× 300

V

′

= 265 ml

Hence, the final volume is 265 ml.

Answer 2

Answer:-

Given:

Initial Volume of a gas (V₁) = 279 cm³

Initial Temperature (T₁) = 87 + 273 = 360° K

Final Temperature (T₂) = 273° K

[ standard temperature of a gas is 273.15° K ≈ 273° K ]

Let the final volume (V₂) = V cm³.

We know that,

Charle's law of gases states that at constant pressure the Volume of a gas is directly proportional to the temperature.

→ V ∝ kT

→ V/T = K

→ V₁/T₁ = V₂/T₂

→ 279/360 = V/273

→ 279 * 273 = 360 * V

→ 279 * 273/360 = V

→ 211.5 cm³ = V

Therefore, the volume of the gas decreases to 211.5 cm³ when it is cooled to standard temperature.