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 C_{p} and C_{v} are specific heats at constant pressure and constant volume respectively. It is observed that

C_{p}-C_{v}=a  for hydrogen gas

C_{p}-C_{v}=b  for nitrogen gas

The correct relation between a and b is :




  • Option 1)

    a= \frac{1}{14}b

  • Option 2)

    a= b

  • Option 3)

    a= 14b

  • Option 4)

    a= 28b


Answers (1)


As we learnt in

Specific heat capacity at constant pressure -

C_{p}= C_{v}+R

= \left ( \frac{f}{2}+1 \right )R

- wherein

f = degree of freedom

R= Universal gas constant


 Cp - Cv = a       (for hydrogen gas)

 Cp - Cv = b        (for nitrogen gas)

 Cp - Cv = R       ( Cp  & Cv   is molar specific heat)

If we convert molar specific heat to specific heat

a = 14 b

Since mass of 1 mole of H2 = 2 g/mole 

mass of 1 mole of N2 = 28 gm/mole

Correct option is 3.

Option 1)

a= \frac{1}{14}b

This is an incorrect option.

Option 2)

a= b

This is an incorrect option.

Option 3)

a= 14b

This is the correct option.

Option 4)

a= 28b

This is an incorrect option.

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