During an experiment, a student observes the formation of a precipitate. Why does this indicate that a chemical reaction is likely occurring? A solid forms, and there is a change of color.
A gas forms, and there is a change of color.
A solid forms, and light is emitted.
A gas forms, and light is emitted.

How does a catalyst increase the speed of a reaction? a. the catalyst eliminates the activated complex stage, allowing products to form immediately. b. the catalyst lowers the energy level of the reactants, making it easier for them to react. c. the catalyst makes it easier for the activated complex to form, lowering the activation energy. d. the catalyst raises the energy level of the products, making the reaction finish sooner. reset next