Is the Molar Specific Heat of Air Similar to Hydrogen?

AI Thread Summary
The discussion centers on the comparison of the molar specific heat of air and hydrogen, with participants noting similarities between hydrogen and the components of air, specifically oxygen and nitrogen. A question is raised about the approximate room temperature in Kelvin and its relevance to the Cv graph for hydrogen. Participants reference a Wikipedia article that discusses the rotational degrees of freedom and their impact on heat capacity at various temperatures. The conversation highlights the complexities of heat capacity in light molecules like hydrogen compared to heavier gases. Overall, the thread seeks clarity on the similarities in molar specific heat among these gases.
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Homework Statement
Estimate the molar specific heat of the air at constant volume Cv by taking into account
major molecules in the air. Plot it as a function of absolute temperature and discuss its
significance.
Relevant Equations
The major chemical elements of air are nitrogen(78%) and oxygen(22%).

The molar specific heat of the air at constant volume for diatomic molecule:
Cv=3/2R (Low Temperature)
Cv=5/2R(High Temperature)
Cv=7/2R(Higher Temperature)
And this is the Cv graph for hydrogen:

1700206012610.png

I think the Cv graph for air is similar with this graph. But I don't know the answer, can someone tell me?
 
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Oxygen and nitrogen are somewhat similar to hydrogen for the purpose of this question.

What is room temperature in Kelvin, very roughly? Where in this graph are we?
 
mfb said:
Oxygen and nitrogen are somewhat similar to hydrogen for the purpose of this question.
Is that true? At https://en.wikipedia.org/wiki/Molar_heat_capacity I read:
"For the rotational degrees of freedom, the thawing temperature is usually a few tens of kelvins (although with a very light molecule such as hydrogen the rotational energy levels will be spaced so widely that rotational heat capacity may not completely "unfreeze" until considerably higher temperatures are reached)."
 
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