14. Analysis

Question 1

Filtration

Answer 1

Used if mixture contains an insoluble solid and a liquid
Mixture is poured into a funnel lined with filter paper
Liquid passes through the filter paper, leaving the solid

Question 2

Crystallisation

Answer 2

Used if your mixture contains a soluble solid and a liquid
Pour solution into an evaporating dish
Slowly heat the solution, some will evaporate stop heating when crystals start to form
Leave in a warm place for rest of liquid to evaporate
Finally dry the product

Question 3

Distillation

Answer 3

Used to separate two liquids
Different liquids have different boiling points
Use a Liebig condenser and heat the mixture
The liquid with the lower boiling point will vaporise
The vapour will then cool and condense in the Liebig Condenser and collected

Question 4

Advantages of using machines to analyse substances

Answer 4

Very sensitive
very fast
Very accurate

Question 5

What does gas chromatography do?

Answer 5

It separates out a mixture of compound to help you identify the substances present

Question 6

How does Gas Chromatography work?

Answer 6

Gas carries substances through column packed with solid materials
Substances travel through the tube at different speed, so they’re separated
Time taken to reach detector = retention time
No. of peaks = no. of substances
Position of the peaks = Retention time

Question 7

What is GC-MS?

Answer 7

When a mass spectrometer is linked to a mass spectrometer

Question 8

What do you find out from the mass spectrometer?

Answer 8

The molecular mass is given by the molecular ion peak