The Last Chapter on Chemistry

Chemical Reaction Two or more substances combining to create something new equals plus

Precipitate A gas or solid given off in a chemical reaction

Chemical Bond The joining of two elements to form a new substance

Chemical Formula Using symbols to abbreviate a compound

Chemical Equation A short way (with symbols) to explain what is happening in a chemical reaction

Reactant What you start with in a chemical reaction

Product What you get after a chemical reaction happens

Law of Conservation of Mass Mass can not be created or destroyed – it can only change form

subscript The numbers to the right and behind a chemical formula

Coefficients The numbers in front of a chemical formula

Synthesis Reaction Two elements added together to create a new compound

Decomposition A reaction that breaks down into smaller elements or compounds

Double Displacement The elements in two compounds trade places

Single Replacement A more active metal replaces a less reactive metal in a compound

Exothermic Gives off heat

Endothermic Takes in heat

Activation Energy Just enough energy to start a reaction

Inhibitor Something that slows down a reaction

Catalyst Something that speeds up a reaction but doesn’t get used up