Paper 2 - Chemical analysis

Question 1

What is a pure substance?

Answer 1

is not mixed with any other substances

Question 2

when does a pure substance melt?

Answer 2

At a specific fixed temperature (specific fixed boiling point) the line is straight and not diagonal on a graph

Question 3

what is a formulation?

Answer 3

A complex mixture that has been designed as a useful product e.g. fuels, cleaning products, paints, medicines

Question 4

Chromatography?

Answer 4

take a piece of chromatography paper and draw a pencil line near the bottom. Then put the dots of our colours on the pencil line. Next place the bottom of the paper in a solvent (a liquid that dissolves substances). the solvent now moves up the paper and dissolves the inks, and the two coloured dots are also carried up the paper

Question 5

in chromatography, how do you know if a colour was pure?

Answer 5

Because there’s only one spot on the paper

Question 6

In chromatography, how do you know if a colour is a mixture?

Answer 6

if the colour has separated into two different colours

Question 7

How do we test for hydrogen?

Answer 7

remove the top of the tube and insert a burning splint. Hydrogen gas burns rapidly and produces a pop sound

Question 8

how do we test for oxygen?

Answer 8

insert a glowing splint into the tube. If it is oxygen, the splint will relight into flames.

Question 9

how do we test for carbon dioxide?

Answer 9

Take some of the carbon dioxide solution and put it into a tube of limewater. If we repeat this several times, the limewater may turn cloudy (carbon dioxide)

Question 10

How do we test for chlorine?

Answer 10

insert a damp litmus paper into the mouth of the test tube. Chlorine will bleach the litmus paper and turn it white