Topic 2 - States of Matter and Mixtures

Question 1

Pure substance

Answer 1

One single element or compound

Question 2

Testing purity

Answer 2

Comparing melting points with expected and actual. Also if the MP is a specific point not a range.

Question 3

Simple distillation

Answer 3

Separating liquid from solution.

Question 4

Limitation of simple distillation

Answer 4

The 2 components must have very different boiling points. If not fractional distillation is used.

Question 5

Fractional distillation use

Answer 5

Mixture of liquids

Question 6

Filtration

Answer 6

Separating an insoluble salt from liquid

Question 7

Crystallisation

Answer 7

Separating a soluble salt

Question 8

Chromatography

Answer 8

Separate a mixture of soluble substances

Question 9

Mobile phase

Answer 9

Where molecules can - water (solvent)

Question 10

Stationary phase

Answer 10

Where molecules can’t move, paper

Question 11

Why pencil is used in chromatography

Answer 11

It’s insoluble so won’t move.

Question 12

If a spot on chromatography doesn’t move

Answer 12

Insoluble

Question 13

Why chemicals move up chromatography paper.

Answer 13

They dissolve in water and are taken with it up the paper.

Question 14

Time taken for chromatography (how far)

Answer 14

How soluble

How attracted to stationary phase

Question 15

Colourless chemicals on chromatogram

Answer 15

Spray with locating agent

Question 16

Rf Value

Answer 16

Distance travelled by solute(chemical)

Distance travelled by mobile phase (water)

Question 17

SRM and Chromotography

Answer 17

Standard reference materials, used to compare and identify a substance.

Question 18

Purity test using chromatography

Answer 18

If there is only 1 spot it’s pure.

Question 19

Sources of UK water

Answer 19

Surface water - lakes, rivers, reservoirs

Ground water - aquifers (rocks trap water underground)

Waste water - from contaminated water from industry

Question 20

Filtration from water treatment

Answer 20

Wire mesh screens out twigs, gravel, sand

Question 21

Sedimentation

Answer 21

Iron or aluminium sulfate are added to water to make fine particles clump together

Question 22

Chlorination and water treatment

Answer 22

Cl2 is bubbles through to kill bacteria or microbes.

Question 23

Distillation and water treatment

Answer 23

In dry countries water is distilled. It requires lots of energy for high amounts.

Question 24

Use of deionised water (distilled)

Answer 24

Ions are removed which could interfere with reactions.