C2 methods of seperation and purification

Question 1

what’s the different between a pure substance and a mixture?

Answer 1

a pure substance only contains one element and isn’t mixed with anything and a mixture is 2 or more elements mixed together

Question 2

using melting point to identify whether it’s a pure compound or a mixture?

Answer 2

wide range of melting points means a mixture, narrow range means a pure compound

Question 3

state some mixtures that can be separated by filtration

Answer 3

sand and water

Question 4

mixtures that can be separated by crystallisation

Answer 4

copper sulphate

Question 5

how to work out Rf value

Answer 5

Rf value = distance moved by compound / distance moved by solvent (solvent front)