Topic 4C.3

[kate 2h]

In the textbook, it gives the molar heat capacity at a constant volume for a monatomic gas, does this only apply to monatomic molecules? How would the molar heat capacity change for diatomic and polyatomic molecules, that have a vibrational contribution to the heat capacity?

[zjfoster25]

Hey! It's funny because I'm using information from my physics class to answer this but there are different specific heats for diatomic and polyatomic gases compared to monatomic ones. For instance, you use the equation (3/2)nRT (n being amt. of moles, R being the gas constant, and T being temperature in kelvin) to calculate the thermal energy of a monatomic gas and (5/2)nRT to calculate the thermal energy of a diatomic gas. The increase in specific heat from 3/2R to 5/2R comes from the extra dimension being filled with the diatomic, being able to not just translate but rotate as well. I am not sure about the nature of polyatomic gases, but maybe someone else can fill us in.