A certain gas is compressed adiabatically. The amount of work done on the gas is $800 \mathrm {~J}$. What is the change in the internal (thermal) energy of the gas?
A) $800 \mathrm {~J}$
B) $0 \mathrm {~J}$
C) $- 800 \mathrm {~J}$
D) $400 \mathrm {~J}$
E) More information is needed to answer this question.

Question

Quizplus · Accepted Answer

According to the first law of thermodynamics, the change in internal energy ($\Delta U$) of a system is equal to the heat added to the system ($Q$) minus the work done by the system ($W$). For an adiabatic process, $Q = 0$, so $\Delta U = -W$. However, in this case, the work is done on the gas, not by the gas, so $\Delta U = +800 \mathrm{J}$.

A Certain Gas Is Compressed Adiabatically 800 J800 \mathrm {~J}800 J What Is the Change in the Internal (Thermal) Energy

A Certain Gas Is Compressed Adiabatically $800 \mathrm {~J}$ What Is the Change in the Internal (Thermal) Energy