Figure 1.01a: (a.)The surface of a single grain of table salt.

CRS Question, 6–8

ANSWER

Choice 3 is in agreement with the result that as a gas expands it does work on the surroundings, which means energy flows out of the system. Since work is calculated using –PDV and DV (final volume – initial volume) is positive, the resulting value for w is negative.

Section 6.1: The Nature of Energy