Chemistry - the study of what things are made of and how things change.
Matter - Anything that has mass and takes up space.
Pure Substance - matter that always has exactly the same composition, or simply a substance
element - substance that cannot be broken down into simpler substances
atom - is the smallest particle of an element
compound - substance that is made from two or more simpler substances and can be broken down into those simpler substances.
mixtures - A combination of substances that are not fixed; they can change
heterogeneous mixture - parts of the mixture are noticeably different from one another.
homogeneous mixture - substance are so evenly distributed that it is difficult to distinguish one substance in the mixture from another
solution - forms when a substance dissolves and forms a homogeneous mixture
suspension - a heterogeneous mixture that separates into layers over time
colloid - contains some particles that are intermediate in size between the small particles in a solution and the larger particles in a suspension
viscosity - the tendency of a liquid to keep from flowing (its resistance to flowing)
conductivity - material's ability to allow heat to flow
malleability - ability of a solid to be hammered into sheets (or shapes) without shattering
melting point - temperature at which a substance changes from solid to liquid.
boiling point - the temperature at which a substance boils
density - ratio of the mass of a substance to its volume (density = mass/volume)
physical property - any characteristic of a material that can be observed or measured without changing the composition of the substances in the material
filtration - process that separates materials based on the size of their particles
distillation - process that separates the substances in a solution based on their boiling points
physical change - occurs when some of the properties of a material change, but the substances in the material remain the same
chemical property - ability to produce a change in the composition of matter
Flammability - material's ability to burn in the presence of oxygen
reactivity - describes how readily a substance combines chemically with other substances
chemical change - occurs when a substance reacts and forms one or more new substances
precipitate - solid that forms and separates from a liquid mixture
solid - state of matter in which materials have a definite shape and definite volume
liquid - state of matter in which a material has a definite volume but not a definite shape
gas - state of matter in which a material has indefinite shape and indefinite volume
plasma - gas-like substance of charged particles; traveling very fast
Kinetic Theory of Matter - states that all of the particles that make up matter are constantly in motion
phase change - reversible physical change that occurs when a substance changes form one state of matter to another
endothermic change - system absorbs energy from its surroundings
exothermic change - system releases energy to its surroundings
Melting - energy is added to a solid object and it turns into a liquid; endothermic
freezing - energy is removed from an object and it goes from a liquid to a solid; exothermic
vaporization - when a substance changes form a liquid into a gas; endothermic
condensation - phase change in which a substance changes from a gas or vapor to a liquid; exothermic
sublimation - phase change in which a substance changes from a solid to a gas or vapor without changing to a liquid first; endothermic
deposition - gas or vapor changes directly into a solid without first changing to a liquid; exothermic