Compare routes without recalculating stored energy

A gas moves between the same equilibrium states (1 L, 60 kPa) and (4 L, 180 kPa). Route A changes volume at 60 kPa and then pressure at fixed volume. Route B changes pressure at fixed volume and then volume at 180 kPa. Both are reversible.

How much greater is QB than QA?

Organize the givens & assumptions

Same initial and final states
ΔV = 3 L
Expansion pressures: 60 and 180 kPa

Closed fixed amount of ideal gas, constant stated heat capacities, negligible bulk kinetic and gravitational energy changes, and only pressure–volume work. Heat into the gas and work by the gas are positive.

A $360\ \mathrm J$
B $0\ \mathrm J$
C $540\ \mathrm J$
D $-360\ \mathrm J$

Try it on paper first. Free sample problems in every collection include the complete reasoning: find one in this collection →