Chapter 21 Vocabulary Study Set
a way to describe a chemical reaction using chemical formulas and other symbols
A combination of chemical symbols and numbers to represent a substance.
represents the number of atoms of an element
large number in from of a compound that represents the number of molecules
Starting materials in a reaction
Ending materials in a chemical reaction.
A reaction in which two or more substances combine to form a new compound: A + B = AB
A reaction in which a single compound breaks down to form two or more simpler substances: AB= A + B
single replacement reaction
double replacement reaction
AB + CD = AD + BC
law of conservation of mass
Mass is neither created nor destroyed in chemical reaction: what goes in must come out
the arrow in the middle of a chemical equation that separates reactants and products
A substance that slows down or stops a chemical reaction
A substance that speeds up the rate of a chemical reaction.
A reaction in which energy is absorbed
A reaction that releases energy in the form of heat or light.