Chapter 1: The Study of Change

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Chemistry - is the study of matter and the changes it undergoes

Matter - anything that occupies space and has mass

- physical property - can be measure and observed without changing the composition or identity of a substance (melting point, boiling point, density, color)

- chemical property - to observe this is a chemical change must be carried out (burning fossil fuels like oil and gas) ( when you burn fossil fuels you get green house gasses, water, heat, and CO2 )

Certain physical and chemical properties can be used to identify a substance

Substance - is a form of matter that has a definite composition and distinct properties

- element - a substance that cannot be separated into simpler substances by chemical means ( about 118 elements total)(82 naturally occurring) (32 related by scientists)

Extensive Property - of a material depends upon how much matter is being considered

- mass, length (cm), volume (cm^3)(v=lxlwh)

Intensive Property -of s material does not depend upon how much matter is being considered

- density(d=m/v)(g/sm^3), temperature

Compound - a substance composed of atoms

of two or more elements chemically united in fixed

proportions

- Compounds can only be separated into their

pure components (elements) by chemical

means

- mixture - combination of two or more substances in which the substances retain their distinct identities

- homogeneous mixture - composition of the mixture is the same throughout

- heterogeneous mixture - it is not the same throughout

Physical means - can be used to separate a mixture into its pure components (iron filings are magnetic so you can use a magnet to operate iron forms sand)

Three States of Matter - Solid, Liquid, Gas

- Substances in a solid form can't move past each, other liquid can, and in gas they have much more room to move

- melting ( solid --> liquid), evaporation (liquid -->gas), condensation(gas -->liquid), freezing (liquid -->solid), sublimation(solid -->gas)

- Physical Change - does not alter the composition or identity of a substance (ice melting, sugar dissolving in water)

- Chemical Change - alters the composition or identity f the substances involved (hydrogen burns in air to form water)

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