Chapter 1, Problem 1.129E

As a child plays on a swing, at what point in her movement is her kinetic energy the greatest? At what point is potential energy at its maximum?

In the following equation for a chemical reaction, the notation s, l, or g indicates whether the substance is in the solid, liquid, or gaseous state:2H2S(g)+3O2(g)2H20(g)+2SO2(g)+energy. Identify each of the following as a product or reactant: a SO2(g); b H2S(g); c O2(g); d H20(g). When the reaction takes place, is energy released or absorbed? Is the reaction endothermic or exothermic?

Use molecular-level drawings to show the difference between physical and chemical changes.