Which term describes a change in a gas's volume, pressure, or temperature that occurs without heat transfer?

Which term describes a change in a gas's volume, pressure, or temperature that occurs without heat transfer?

• A. Adiabatic Change
• B. Isothermal Change
• C. Isobaric Change
• D. Isochoric Change

Answer: (A)

Adiabatic change means no heat transfer occurs between the system and its surroundings. When a gas undergoes a change in volume, pressure, or temperature without exchanging heat, the energy change comes entirely from work done on or by the gas. For an ideal gas, this leads to temperature shifting as the gas is compressed or expanded, because the internal energy is tied to temperature and the work input or output changes that energy. A key relationship in this case is PV^γ = constant, where γ is the ratio of specific heats; this links pressure and volume as the gas changes, and the temperature adjusts accordingly (compression raises temperature, expansion lowers it). Other processes involve heat transfer or have constraints that prevent simultaneous changes in all three properties without heat flow: isothermal changes keep temperature constant by exchanging heat to balance the work done, isobaric changes keep pressure constant, and isochoric changes keep volume fixed, so no work is done and temperature changes only due to heat transfer. The description given—no heat transfer with changes in volume, pressure, or temperature—best matches an adiabatic process.

Adiabatic change means no heat transfer occurs between the system and its surroundings. When a gas undergoes a change in volume, pressure, or temperature without exchanging heat, the energy change comes entirely from work done on or by the gas. For an ideal gas, this leads to temperature shifting as the gas is compressed or expanded, because the internal energy is tied to temperature and the work input or output changes that energy. A key relationship in this case is PV^γ = constant, where γ is the ratio of specific heats; this links pressure and volume as the gas changes, and the temperature adjusts accordingly (compression raises temperature, expansion lowers it).

Other processes involve heat transfer or have constraints that prevent simultaneous changes in all three properties without heat flow: isothermal changes keep temperature constant by exchanging heat to balance the work done, isobaric changes keep pressure constant, and isochoric changes keep volume fixed, so no work is done and temperature changes only due to heat transfer. The description given—no heat transfer with changes in volume, pressure, or temperature—best matches an adiabatic process.