In the context of thermodynamics, an 'ideal gas' is a hypothetical gas whose molecules occupy negligible space and have no interactions, except for elastic collisions. An ideal gas follows the ideal gas law, which is generally stated as \( PV = nRT \), where
- \( P \) is the pressure,
- \( V \) is the volume,
- \( n \) is the number of moles of the gas,
- \( R \) is the universal gas constant,
- \( T \) is the absolute temperature.
The consideration of a gas being ideal does not affect the calculations for the change in internal energy or the work done in our original problem, because these calculations rely only on measurable parameters such as pressure, volume, and heat. It's when we need to understand how gases behave on a micro-level, considering relationships like pressure, volume, and temperature, that the ideal gas model becomes significant.
While real gases deviate from the ideal gas model under high pressure and low temperature, for many practical purposes, the ideal gas law provides helpful approximations, simplifying calculations and predictions about gas behavior. In our exercise, discussing whether the gas is ideal is more relevant to theoretical interests rather than affecting practical outcomes in these specific calculations.