Section 11 - States of Matter and Mixtures

Question 1

States of Matter and Changes of State - Name the three states of matter

Answer 1

Solid, Liquid and Gas

Question 2

States of Matter and Changes of State - Describe the arrangement of particles and the forces between them in a solid

Answer 2

• Strong forces of attraction hold particles in fixed positions in a regular lattice arrangement

Question 3

States of Matter and Changes of State - What happens to the forces between the particles in a solid as you melt it?

Answer 3

The hotter the solid becomes, the more they vibrate, meaning that the solid will expand slightly when heated

Question 4

States of Matter and Changes of State - What do you call the process of a substance changing from a liquid to a solid?

Answer 4

Freezing

Question 5

Purity and Separating Substances - What is the chemical definition of purity?

Answer 5

Pure = a substance is pure if it is completely made up of a single element or compound

Question 6

Purity and Separating Substances - Explain why air isn’t considered a pure substance

Answer 6

Because it’s a mixture of nitrogen, oxygen, argon, carbon dioxide, water vapour and various other gases

Question 7

Purity and Separating Substances - Where is the hottest part of a fractionating column, at the top or at the bottom?

Answer 7

The bottom

Question 8

Purity and Separating Substances - What separation technique should you use to separate a soluble solid from a solution?

Answer 8

Crystallisation

Question 9

Purity and Separating Substances - Explain what the terms ‘mobile phase’ and ‘stationary phase’ mean in chromatography

Answer 9

Mobile phase = where the molecules can move (liquid or a gas)
Stationary phase = where the molecules can’t move (solid or a thick liquid)

Question 10

Water Treatment - Name three different sources of water that can be made potable

Answer 10

1) Surface water (from lakes, rivers and reservoirs)
2) Ground water (from aquifers)
3) Waste water (water that has been contaminated)

Question 11

Water Treatment - Name three processes that are used to make water potable

Answer 11

1) Filtration — a wire mesh screens out large twigs etc. then gravel and sand beds filter out other solids
2) Sedimentation — iron sulfate added to water to make fine particles clump together at the bottom
3) Chlorination — chlorine gas bubbles through to kill harmful bacteria and other microbes

Question 12

Water Treatment - What is deionised water?

Answer 12

Deionised water = water that has had the ions that are present in normal tap water removed