Chemistry definitions

MIXTURE: Contains two or more substances not chemically joined together.
ALLOY: A mixture that contains at least one metal.
COMPOUND: A substance formed when two or more different elements are chemically joined together.
FORMULA: The number of atoms of each element in a compound.
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CHEMICAL EQUATION: An equation to show reagents changing into products.
REAGENT: Chemicals at the start of a chemical reaction.
PRODUCT: Chemicals that are formed during a chemical reaction.
COMBUSTION: A reaction in which a fuel combines with oxygen and gives out energy and a flame.
EXOTHERMIC: A reaction that gives out energy (gets hotter).
ENDOTHERMIC: A reaction that takes in energy (Gets colder).
PRECIPITATION: A reaction in which a solid is produced from at least one solution.
DECOMPOSITION: A reaction in which a compound is broken down into simpler substances.
THERMAL DECOMPOSITION: A reaction in which a compound is broken down by heat into simpler substances.
SYNTHESIS: A reaction in which two or more substances combine to form a more complex product.
DISPLACEMENT: A reaction in which a more reactive element takes the place of a less reactive element in a compound.
EFFERVESCENCE: A fizzing made when a gas is produced.
PRECIPITATE: Cloudy, insoluble solid product formed during a precipitation reaction.
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OXIDE: An element combined with oxygen to form a new compound.
BASE: A base is a substance with a pH of 8-14
[Base is short for Basic Oxide (metal oxides are bases)].
ALKALI: A soluble base, also has a pH of 8-14
(metal hydroxides are alkalis).
ACID: A substance with a pH of 0-6.
INDICATOR: A substance that changes color when in different pH.
pH: A scale to measure the acidic or basically of a chemical
NEUTRALISATION: When an acid reacts with a base to form salt and water only.
SALT: A compound formed when the hydrogen of an acid is replaced by a metal.