Gas molecules of different masses in the same container have the same average transnational kinetic energy which is directly proportional to their_____________?
Correct answer: C. absolute temperature
- A. volume
- B. pressure
- C. absolute temperature
- D. time
Explanation
The average translational kinetic energy of a molecule is (3/2)kT, where k = 1.38 x 10^-23 J K^-1 and T is absolute temperature in kelvin. It therefore depends on absolute temperature, not molecular mass, so gases at the same temperature have the same average translational kinetic energy. The likely trap is choosing b because pressure is related to molecular motion, but pressure also depends on number density and volume.
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About Thermal Equilibrium and Heat
Thermal equilibrium means that bodies in contact have the same temperature and no net heat flows between them. The topic distinguishes heat from temperature, uses the zeroth law of thermodynamics, and covers heat transfer, specific heat capacity, thermal expansion and the conditions for reaching equilibrium.
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