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A gaseous mixture contains 2 moles of oxygen and 4 moles of argon at temperature T. If vibrational degrees of freedom are ignored, what is the total internal energy of the mixture?
- 4 RT
- 15 RT
- 9 RT
- 11 RT
Correct answer: 11 RT
Solution
The total internal energy of an ideal gas is calculated using the formula U = (f/2) nRT, where f is the degrees of freedom. For this mixture, oxygen has 5 degrees of freedom (3 translational + 2 rotational) and argon has 3 degrees of freedom (3 translational), leading to a total of 11 degrees of freedom for 6 moles of gas, resulting in an internal energy of 11 RT.
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