Every chemical reaction involves a change in energy because different substances hold different amounts of energy. During the reaction, bonds inside the substances that are reacting together must ...

Students recognize that a particular color change is a characteristic property of a substance and that a color change can also be used as evidence that a chemical reaction has occurred. Students will ...

Enzymes are large biological molecules—usually proteins—that speed up chemical reactions. Molecules that speed up chemical ...

A chemical reaction is when one or more substances change and produce one or more new chemical substances. The substances that are involved in a chemical reaction and that are changed by it are ...

Controlling matter at the atomic level has taken a major step forward, thanks to nanotechnology research by an international ...