Chem unti 1 test

Classification of Matter Separation of Mixtures Physical & Chemical Changes & Properties States of Matter

Percent Error Formula

Precision

measure of how closely individual measures agree with one another

Accuracy

refers to how closely individual measures agree with the correct or true value

Ex #1

accurate & precise

Ex #2

accurate, not precise

Ex #3

precise, not accurate

Ex #4

not accurate, not precise

Scientific Notation

a short hand method to write very large & very small numbers, This notation uses a coefficient (a number between 1 and 10) and a power of ten sufficient for the actual number

Pure Substance

uniform & definite composition, cannot be separated by physical means

Element

cannot be broken down by chemical means, found on PT, 1 type of atom only

Compound

2 or more different elements chemically bonded in a fixed proportion, can be separated chemically into elements

Diatomic

any substance made up of only 2 atoms

Mixture

Physical blend of 2 or more substances, can be separated by physical means, proportions can vary

Homogeneous Mixture

uniform throughout, also known as solution, gases will be homogeneous

Heterogeneous Mixture

non-uniform throughout e.g sand & water

Filtration

Mixture of solid & liquid is poured through porous medium - liquid passes through while solid remains

Distillation

separation of substances based on boiling point

Chromatography

separation of substances based on their ability to adhere to various solids e.g paper

Physical Properties

Characteristics that can be observed w/ out altering the identity of the substance

density, color, melting point, state of matter

Chemical Properties

Characteristics of a substance that cannot be observed without altering the substance

flammability

Physical Change

Does not alter the identity of the substance

phase change

Chemical Change

Alters the identity of the substance

burning

Indications of Chemical change

Transfer of energy, change in color, production of a gas, formation of a precipitate, change in pH

Solid

Definite shape & volume, not easily compressed, strong forces of attraction between particles

Liquid

Indefinite shape, definite volume, not easily compressed, weak forces of attraction between particles

Gas

Indefinite shape, indefinite volume, easily compressed, no attraction between particles

Sublimation

Solid to Gas

Deposition

Gas to Solid

Melting

Solid to Liquid

Freezing

Liquid to Solid

Vaporization

Liquid to Gas

Condensation

Gas to Liquid