Which of the following is an example of oxidation? a: when a pond freezes over. b: when cocoa mix dissolves in milk. c: when rust forms on a nail d: when heat and light is given off a burning log.

Which statement is true about a catalyst? a: a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.