Mixtures

Question 1

What does a mixture consist of?

Answer 1

Two or more elements or compounds not chemically combined together

Question 2

The chemical properties of substances in a mixture are unchanged

True or False?

Answer 2

True

Question 3

Name 3 physical processes used to separate mixtures

Answer 3

Filtration
Crystallisation 
Simple distillation
Fractional distillation
Chromatography

Question 4

Give an example of when chromatography is used

Answer 4

To compare ink samples from pens

Question 5

What is distillation?

Answer 5

Separating 2 liquids from each other

Question 6

Stages of distillation

Answer 6

Heat the mixture of liquids
Liquid with lower BP evaporates 
Vapour cools and condenses into a liquid
Liquid drops down the condenser 
The liquid comes down through the condenser and is collected the beaker

Question 7

Why is chromatography used?

Answer 7

To separate pigments such as ink.

The pigments have different solubilities and move at different rates in the solvent up the filter paper

Question 8

What value is used to analyse chromatograms

Answer 8

R values

f

Question 9

What does R stand for?

f

Answer 9

Retention factor

Question 10

What is the equation for the Rf value?

Answer 10

Distance moved by the substance

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Distance moved by the solvent