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

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