Elements, Compounds and Mixtures

a substance that consists of only one type of atom and it cannot be broken down into anything simpler by chemical means

2 or more different elements chemically bonded together

a group of elements that can be separated and aren’t chemically bonded together

fixed melting/boiling point

can melt/boil at different temperatures as its not solely one pure element

separating a liquid from a solution • boil the mixture • water vapour of the liquid with the lower boiling point condenses back into a liquid when passed through a condenser • pure substance is left behind the flask commonly used to purify water or separate alcohol from water

separating a mixture of different liquids with different boiling points • boil the mixture until it reaches the lowest boiling point of one of the liquids • that water vapour condenses back into a liquid • repeat for all boiling points from the lowest to highest commonly used for separating crude oil

separating an insoluble solid from a liquid • pour the mixture into filter paper • filtrate (liquid) passes through and is collected in the conical flask • insoluble solid is left in the filter paper

obtaining a salt containing water of crystalisation from a salt solution • heat solution in crucible to evaporate water until crystals form • leave to cool and filter to get rid of excess liquid • pat dry with towel and leave in a warm place to evaporate any excess liquid