**What is the relation (analogous to the ideal gas law) between the pressure and the average velocity?**Eq. (1.14), P = N m < v

_{x}^{2}>, where <.> means ``average'' (I don't know how to make an overline in html). Equivalently, you could use the velocity instead of the x-component with P = N m < v^{2}> /3, where <.> means ``average''**Is equation (1.20) true for non-ideal gasses?**Yes, oddly enough. We'll learn why later.

**Does a diatomic molecule have a higher or lower thermal energy than a monatomic molecule?**Higher. U = (5/2) N k T for a diatomic molecule (assuming the bond isn't oscillating) and U = (3/2) N k T for a monatomic molecule.

**What is the average thermal energy for a diatomic gas at very high temperatures (neglecting relativity)?**When the bond begins to oscillate, which is usually much higher than room temperature, then there are 7 degrees of freedom instead of 5, so U = (7/2) N k T.

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