Chemical Reactions

Physical Change

A change that does not alter the chemical identity of a substance; no new substance formed, typically reversible.

Chemical Change

A change that results in the formation of new chemical substances; usually not reversible.

Synthesis Reaction

A type of reaction where two or more substances combine to form one product.

Decomposition Reaction

A chemical reaction where one compound breaks down into two or more simpler substances.

Precipitate

An insoluble solid that forms from a liquid solution during a chemical reaction.

Collision Theory

The theory that states chemical reactions only occur when reactant particles collide with sufficient energy and in the correct orientation.

Endothermic Reaction

A reaction that absorbs heat, resulting in a decrease in temperature of the surroundings.

Exothermic Reaction

A reaction that releases heat, resulting in an increase in temperature of the surroundings.

Acid + Metal

A reaction between an acid and a metal producing a salt and hydrogen gas.

Acid + Metal Hydroxide

A reaction between an acid and a metal hydroxide producing a salt and water.

Acid + Metal Carbonate

A reaction between an acid and a metal carbonate producing a salt, water, and carbon dioxide.

Gas Formation

A sign of a chemical reaction where gas bubbles are produced, often indicating a reaction is occurring.

Temperature Change in Reactions

Observational change where the reaction might feel warm (exothermic) or cold (endothermic) to the touch.

Soluble Substance

A substance that dissolves in water to form a clear solution.

Insoluble Substance

A substance that does not dissolve in water and remains solid.

Clear Solution

A liquid that is fully transparent, allowing one to see through it.

Colourless Liquid

A liquid that is transparent with no color.

Balanced Chemical Equation

An equation that has the same number of each type of atom on both the reactant and product sides.