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

CRS Question, 6–21

ANSWER

Choice 3 provides both the proper sign and value for the new reaction. The original reaction must be reversed in order to show oxygen forming ozone. This means the given sign for DH must also be reversed. Since the reversed reaction shows the process for 3 moles of oxygen, the DH value must be reduced by 1/3 to determine the value for only one mole.

Section 6.3: Hess’s Law