ap chem unit 4.1,

homogenous mixture

composition is uniform throughout (ex. salt and sugar)

heterogenous mixture

composition is visibly different (ex. trail mix)

pure substance

has a uniform and definite chemical composition. elements and chemical compounds

compounds

substance with a constant chemical composition that can be broken down into elements 

element

substance that can’t be broken down into simpler substances

physical change

reversible change in a substance that doesn’t change it’s chemical composition

physical changes between gases and liquids

vaporization- liquid to gas

condensation- gas to liquid

physical changes between liquids and solids

fusion/melting- solid to liquid

freezing- liquid to solid

physical changes between gases and solids

sublimation- straight from solid to gas

deposition- straight from gas to solid (ex. frost formation)

other types of physical changes?

separations of mixtures and deformations of the substance, like cutting, tearing, etc.

4.1 chemical change

change in a substance that changes its identity. breaking of bonds and formation of new bonds.

evidence of chemical changes

precipitate, unexpected color and temperature change, light, evolution of a gas, formation of substance with new properties

composition/synthesis reactions

two or more reactants combine to form a single product. A + B ----> AB

4.1 decomposition reactions (redox)

compound is broken down into elements AB---> A + B

single ionic replacement

one element replaces another in a compound. can be a cation or anion. A + BC ---> AC + B

double ionic replacement

two element/compounds replace each other in a reaction. AB + CD ----> AD + CB

combustion of a hydrocarbon

chemical reaction with oxygen that produces carbon dioxide and water

combustion of a metal