Question

The temperature of 5 mole of a gas which was held at constant volume was changed from 100^oC to 120^oC. The change in internal energy was found to be 80 J. The total heat capacity of the gas at constant volume will be equal to

• A. $8JK^{- 1}$
• B. $0.8JK^{- 1}$
• C. $4JK^{- 1}$
• D. $0.4JK^{- 1}$

Answer 1

Answer: (C)

$4JK^{- 1}$

Answer 2

At constant volume total energy will be utilised in increasing the temperature of gas

i.e. $(\Delta Q)_{v} = \mu C_{v}\Delta T$ $= \mu C_{v}(120 - 100) = 80$

⇒ $\mu C_{v} = \frac{80}{20} = 4$ Joule/kelvin.

This is the heat capacity of 5 mole gas.