Question

A gas goes from 1L at 273 K to 2 L when heated. What is the new temp?

Answer 1

Answer:

Given : Diatomic molecule at 273K

'q' absorbed = positive = +100Cal = 100 x 4.184J = 418.4J

'W' done by system = negative = -209J

By first law of thermodynamics;

ΔU = q + W = 418.4 + (-209) = 209.4J

We know for diatomic molecule Cv=25R and CvΔT=ΔU

CvΔT=209.4

 25RΔT=209.4

ΔT=5R209.4×2

And, Heat exchange=Cm×ΔT 

where; Cm is molar heat capacity

Cm=ΔTHeat Exchange

substituting values for Heat Exchange = 418.4 and ΔT=5R209.4×2

Cm=5R