Question

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

Answers

  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

    Reply

Leave a Comment