Two moles of an ideal gas in a frictionless piston–cylinder device undergo the…
CHEMISTRY · Single correct · AP · Chemistry · Thermochemistry · Thermochemistry
Problem
Two moles of an ideal gas in a frictionless piston–cylinder device undergo the following sequence at 298 K:
1. An isothermal expansion that performs 15 kJ of pressure–volume work on the surroundings.
2. A subsequent cooling at constant volume that releases 20 kJ of heat to the surroundings.
Which combination of signs for q, w, and ΔE describes the overall process, and how should the process be classified with respect to heat flow?
(a) q<0, w>0, ΔE<0; the overall process is exothermic
(b) q>0, w<0, ΔE>0; the overall process is endothermic
(c) q<0, w<0, ΔE<0; the overall process is exothermic
(d) q>0, w<0, ΔE<0; the overall process is exothermic