The speed of sound in hydrogen at 0°C is 1280 m s^–1. The density of hydrogen at STP is 0.089 kg m^–3. Calculate the molar heat capacities C_P and C_V of hydrogen.

Given:

The speed of sound in hydrogen at 0°C is 1280 m s^–1.

The density of hydrogen at STP is 0.089 kg m^–3.

At STP the pressure P is 1.013×10⁵Pa.

So the speed of sound in hydrogen where is the density of the gas.

So, putting data in, we get,

So, ;