Which of the following can change for a fixed mass of gas?

A fixed mass of gas can have its pressure, volume, and temperature change due to the interrelated nature of these properties as outlined in the gas laws. According to the ideal gas law, which states ( PV = nRT ), where ( P ) is pressure, ( V ) is volume, ( n ) is the number of moles (fixed in this case), ( R ) is the ideal gas constant, and ( T ) is temperature, any change in one of these properties will affect the others.

For instance, if the volume of a gas expands while the amount of gas remains constant, the pressure must decrease if the temperature is held constant. Conversely, if the temperature increases while the volume is constant, the pressure must increase. This illustrates that not only can pressure change, but volume and temperature can also change in a fixed mass of gas.

In summary, a fixed mass of gas can indeed have all three properties—pressure, volume, and temperature—altered simultaneously.