chemistry

Ionic bonding

Metal + non metal-metal atom gives away electrons to non metal atom-creates oppositely charged ions that act like magnets

Covalent bonding

Metal + metal-two non metal atoms share electrons

Metallic bonding

Metal + metal-metal atoms pack closely together and let their outer electrons wander completely free- creates a sea of delocalised electrons holding positive metal ions together

Filtration

Separates mixture of liquid and insoluble solid-liquid passes through filtration paper but large solid particles get trapped

Crystallisation

separating something that dissolves from a liquid when you want to keep the solid salt-heat solution to evaporate liquid leaving behind pure salt crystals

Fractional distillation

Liquid and liquid-separating a mixture of two or more liquids with different boiling points-liquid with lowest boiling point evaporates first passes through fractionating column and condenses at the top to be collected first

Simple distillation

soluble solid and liquid-separating a dissolved solution from a liquid when you want to keep pure liquid-heat mixture liquid evaporates travels down cooling tube turns back into liquid and drips into separate beaker

Making water safe

1 Sedimentation: The water is stored in a tank so large pieces of dirt sink to the bottom.

2 Filtration: The water is passed through layers of sand and gravel to trap smaller particles.

3 Chlorination: Chlorine gas is bubbled through the water. Chlorine kills bacteria and microbes to prevent diseases.

moles equation

Moles=mass/Mr

What is Mr

Atomic mass number

Empirical formula-MAMD

1.Write down mass number of each element given

2.Find the atomic mass number

3.Divide mass number by atomic number to find moles

4.Divide moles by smallest mass number and times both by the amount needed to make them whole numbers if they aren’t

Work done equation

Work done(j)=force(n) x distance moved(m)

Gravitational potential energy

energy an object has because it has been lifted up.