急AL phy-gas internal energy

internal energy = 3/2 nRT
n and R are constant in this case
vol increase doesn't imply an increase in temperature, therefore false

2011-01-16 11:16:03 補充：
for ideal gas, it is assumed that the gas molecules doesn't have any interaction between each other, therefore the potential energy of ideal gas is 0.

The internal energy of an ideal gas depends on its temperature only.For a given mass of gas, the internal energy doesn't depend on its volume.

The reason is straight forward. The potential energy of molecules in an ideal gas has already reached the max value (i.e. zero potential energy). Any change in volume doesn't not lead to change in potential energy.

For the kinetic energy of molecules, this depends on temperature. Any increase or decrease of temperature leads to an increase or decrease of molecular kintic energy, hence a change of internal energy.