版权所有：华东理工大学物理化学教研室 5 The direction of spontaneous change Some things happen naturally. A gas expands to fill the available volume, a hot body cools to the temperature of its surroundings, and a chemical reaction runs in one direction rather than another. But some things don't. We can confine a gas to a smaller volume, we can cool an object with a refrigerator, and we can force some reactions to go in reverse. However, none of these processes happens spontaneously.版权所有：华东理工大学物理化学教研室 5 The direction of spontaneous change Some things happen naturally. A gas expands to fill the available volume, a hot body cools to the temperature of its surroundings, and a chemical reaction runs in one direction rather than another. But some things don't. We can confine a gas to a smaller volume, we can cool an object with a refrigerator, and we can force some reactions to go in reverse. However, none of these processes happens spontaneously