Question

In: Physics

4a) sketch a graph of the heat capacity per molecule of a diatomic gas (e.g. N2)...

4a) sketch a graph of the heat capacity per molecule of a diatomic gas (e.g. N2) versus temperature. Label the vertical axis clearly and show room temperature on the horizontal axis. Explain in a few words the main function of the graph.

4b) Express the heat capacity per molecule or per mole (please specify which) at low temperature in real units, i.e. in Joules/ Kelvin or Joules/ mole-Kelvin.

Thank you in advance for your help!

Solutions

Expert Solution

a) the heat capacity of a diatomic molecule vs temperature graph is as shown below.

the specific heat capacity has three parts,

1. Translational

2. Rotational

3. vibrational

here each curve represents the change in specific heat capacity due to above three motions of a diatomic molecule like N 2 .

but the translational motion for specific heat capacity at constant volume is at 3/2 R an at constant pressure is 5/2 R.

b) the expression for the specific heat capacity at constant volume is given by using the Debye temperature

that is,

where TD is the Debye temperature.

units of Cv is (J/K mole)


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