Topic 2- States of matters and mixtures

Question 1

Name given when a solid that turns into gas

Answer 1

subliming

Question 2

What does it mean if a substance is pure?

Answer 2

Its made up of one element or compound

Question 3

What do every pure substance do?

Answer 3

Have a specific sharp melting and boiling points

Question 4

What is distillation used for?

Answer 4

To separate liquid from a solution

Question 5

Explain simple and fractional distillation

Answer 5

answer on CARD 11

Question 6

What is filtration used for ?

Answer 6

to separate insoluble solid from a liquid

Question 7

What is crystallisation used for?

Answer 7

to separate soluble solid from a solution

Question 8

Explain the process of crystallisation?

Answer 8

1. Pour the solution into the evaporating dish and gently heat it up
2. Some of the water will evaporate, so the solution will become more concentrated
3. The salt should start to form crystals when it becomes insoluble in the cold.
4. Leave them to dry ( in a drying oven).

Question 9

State the two phases that chromatography uses;

Answer 9

• A mobile phase ( solvent) ; where the molecules can move - liquid or a gas
• A stationary phase (piece of filter paper\\0: where the molecules can’t move - solid or a thick liquid

Question 10

Describe the chromatography process

Answer 10

1. Draw a line at the near the bottom of the paper using a pencil
2. Then put some of your solvent in the beaker , just below the BASELINE
3. Also put a watch glass on top of the beaker to stop any solvent from evaporating
4. The you will start to see that different chemicals in the sample will separate out.
5. Then remove the paper and measure the distance measured by the solvent.

Question 11

How do you measure the distance of the chemical in chromatography if your solution is colourless.

Answer 11

Spray it with locating agent

Question 12

How do you workout the Rf ( in chromatography ) ?

Answer 12

distance travelled by solute
. divide
distance travelled by solvent

Question 13

Water sources in the UK:

Answer 13

• Surface water- lakes, rivers and reservoirs
• Ground water- coming from the ground
• Waste water- water that has been contaminated, by human process

Question 14

How is water purified?

Answer 14

1. Firstly it is filtrated , where large pieces are collected, e.g twigs
2. Then comes sedimentation, where iron sulfate or aluminium sulfate is added , which makes fine particles clump together at the bottom
3. Then comes chlorination, where chlorine is added to kill bacteria.

Question 15

Why should the water used in chemical analysis should be pure

Answer 15

Because tap water contains other ions which might interfere in the practical. But deionised water should be used.