a change that alters the form or appearance of a material but does not make the material into another substance

a reaction that releases energy, usually in the form of heat

a change in which one or more substances combine or break apart to form new substances

a solid that forms from a solution during a chemical reaction

a substance formed as a result of a chemical reaction

a substance that enters into a chemical reaction

a material that decreases the rate of a reaction

the minimum amount of energy needed to start a chemical reaction

the amount of one material in a certain volume of another material

A biological catalyst that lowers the activation energy of reactions in cells

a reaction in which one element replaces another in a compound or when two elements in different compounds trade places

H₂ + O₂ --> H₂O₂ is an example of a

The principle that the total amount of matter is neither created or destroyed

a system in which matter can enter from or escape to the surroundings

a number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved in a reaction

a chemical reaction in which two or more simple substances combine to form a new, more complex substance

a chemical reaction that breaks down compounds into simpler products

A material that increases the rate of a reaction by lowering the activation energy