Question

An ideal gas in a sealed container has an initial volume of 2.55 L. At constant pressure, it is cooled to 20.00 °C where its final volume is 1.75 L. What was the initial temperature?

A sample of xenon gas occupies a volume of 9.47 L at 403 K. If the pressure remains constant, at what temperature will this same xenon gas sample have a volume of 6.29 L?

Answer 1

ans)

1)

According to Charles law, V₁/T₁ = V₂/T₂

or, T₁ = V₁T₂ / V₂

V₁ = initial volume = 2.55 L

V₂ = final volume =1.75 L

T₂ = Final temperature = 20 ^oC = (273 + 20 ) K = 293 K

T₁ = Initial temperature = ?

Hence, T₁ = ( 2.55L x 293K) / 1.75 L= 426.9 K= (426.9 - 273) ^oC = 153.9^oC

T₁ = Initial temperature = 154.0 ^oC

2)

Given,

V1 = 9.47 L = 9.47 x 10^-3 m^3

T1 = 403 K

V2 = 6.29 L = 6.29 x 10^-3 m^3

Let P1 = P2 = P

and T2 = T

We know that,

P1 V1 / T1 = P2 V2 / T2

=> P x 9.47 x 10^-3 / 403 = P x 6.29 x 10^-3 / T

=> T = 266.7 K = Temperature at which this same xenon gas sample have a volume of 6.29 L