atomic structure

what are all substances made from

atoms

define compounds

a substance that consists of two or more elements chemically combined.

water is a compound what two elements make up water

hydrogen and water

what does the compound water contain

1 oxygen atom and 2 hydrogen atoms

define an atom

the smallest particle of a chemical element

define an element

a molecule with two or more atoms of different elements bonded together

what can the term molecule be used to describe

compounds

what are all atoms made up of

a tiny central nucleus with electrons orbiting around it

what two things do chemical equations show

the reactants and the products

what does it mean if a chemical equation is balanced

the total mass of the products formed in the reaction is equal to the total mass of the reactants

what is the law of conservation mass

the total mass of the products formed in a reaction is equal to the total mass of the reactants

what is a mixture made up of

two or more substances that are not chemically combined

what are the four separation techniques

filtration

crystallisation

distillation

chromotography

define filtration

used to separate substances that are insoluble in a particular solvent from from those that are soluble in the same solvent