Physics

Problem

A gas in a cylinder undergoes the following two-step process: Step 1: At constant pressure the gas expands, doing

300\,\text{J}

of work on the surroundings while

150\,\text{J}

of energy is simultaneously transferred into the gas by heating. Step 2: With the piston locked in place, the gas is cooled at constant volume, and

100\,\text{J}

of energy is removed from the gas by heating. What is the net change in internal energy

\Delta U_{\text{net}}

for the gas for the combined process, and did the system ultimately gain or lose energy? a)

+350\,\text{J}

; the system gained energy b)

-250\,\text{J}

; the system lost energy c)

+50\,\text{J}

; the system gained energy d)

+250\,\text{J}

; the system gained energy