C6

Question 1

What charge is on the cathode?

Answer 1

The cathode is negative.

Question 2

What charge is on the anode?

Answer 2

The anode is positive.

Question 3

What is electrolysis?

Answer 3

Electrolysis is the flow of charge by the movement of ions to electrodes.

Question 4

What is made during the electrolysis of sulphuric acid?

Answer 4

During the electrolysis of sulphuric acid H₂ is made at the cathode and O₂ at the anode.

Question 5

What two factors affect the amount of substance deposited at each electrode?

Answer 5

The two factors that affect the amount of current deposited is the time and current.

Question 6

Construct the balanced symbol equation between H₂ and O₂

Answer 6

2H₂ + O₂ —-> 2H₂O

Question 7

Construct the balanced symbol equation for reaction in a fuel cell.

Answer 7

Question 8

Give 3 the advantages of using fuel cells in spacecraft.

Answer 8

Don’t have to carry heavy fuel

Doesn’t take up much space

Produces no pollution

Question 9

Give 2 reasons why the car industry is developing fuel cells.

Answer 9

The car industry is developing fuel cells as petrol is running out and there are environmental concerns about the amount of pollution from petrol cars.

Question 10

Write a word equation for rusting.

Answer 10

Iron + oxygen + water —-> Hydrated Iron Oxide.

Question 11

What do redox reactions involve?

Answer 11

Redox reactions involve oxidation and reduction.

Question 12

What is reduction?

Answer 12

Reduction is the gain of electrons.

Question 13

What is oxidation.

Answer 13

Oxidation is the loss of electrons.

Question 14

In what 2 ways does galvanising iron prevent rusting.

Answer 14

Galvanising iron with zinc acts as a barrier to rusting and galvanising zinc acts as a sacrificial metal.

Question 15

Construct word equation for the reaction between sodium and copper chloride solution. What do we call this type of reaction displacement reactions

Answer 15

sodium + copper chloride solution = copper metal + sodium chloride solution.

This is called a displacement reactions

Question 16

Construct a word equation for the reaction between potassium and copper chloride solution. What do we call this type of reaction reaction?

Answer 16

copper chloride solution + potassium = Copper metal + potassium chloride solution.

This is called a displacement reactions

Question 17

Construct a word equation for the reaction between sodium and silver chloride solution. What do we call this type of reaction reaction?

Answer 17

sodium + silver chloride solution = silver metal + sodium chloride solution

This is called a displacement reaction.

Question 18

What is the molecular formula and displayed formula of ethanol?

Answer 18

C₂H₅OH

Question 19

Write the word and balanced symbol equations for fermentation.

Answer 19

Glucose + Oxygen = Carbon dioxide + energy + water

Question 20

Why is ethanol made by fermentation, a renewable fuel

Answer 20

Crops that are used to make ethanol can be grown again in a few months.

Question 21

Why is ethanol made from ethene a non-renewable fuel?

Answer 21

Ethene is produced from crude oil and once crude oil is used it takes millions of years to replace it.

Question 22

What is the catalyst that hydration of ethane needs.

Answer 22

The catalyst that hydration of ethane needs is phosphoric acid catalyst.

Question 23

Explain why the use of CFCs has been banned in the UK.

Answer 23

They create holes in the ozone layer.

Question 24

How do CFCs deplete the ozone layer.

Answer 24

CFCs deplete the ozone layer by breaking the bonds between O₃ molecules which make up ozone.

Question 25

What is it that reacts with the ozone?

Answer 25

Highly reactive chlorine atoms react with ozone.

Question 26

How does depletion of the ozone layer let more UV reach Earth?

Answer 26

Ozone layer absorbs most of the uv light from the Sun, stopping it reaching the earths surface.

Question 27

What can we replace harmful CFCs with?

Answer 27

CFCs can be replaced with alkanes or HFCs.

Question 28

What causes the origin of temporary hardness in water?

Answer 28

Water travels across rocks which are rich in magnesium hydrogen carbonate or calcium hydrogen carbonate.

Question 29

How can temporary hardness be removed from water?

Answer 29

Temporary hardness can be removed from water by boiling it.

Question 30

What causes permanent hardness in water?

Answer 30

Permanent hardness is caused by calcium sulfate.

Question 31

How does boiling remove temporary hardness in water.

Answer 31

It makes the soluble calcium hydrogen carbonate become the insoluble calcium carbonate.

Question 32

What would you measure to show if water is hard or soft?

Answer 32

The froth on the soapy water.

Question 33

How would you describe animal and vegetable fats and oils.

Answer 33

Animal and vegetable fats and oils are esters.

Question 34

Describe how bromine water is used to show unsaturation in oils.

Answer 34

Add bromine water and if the oil is unsaturated the bromine water goes colourless.

Question 35

How is margarine manufactured from vegetable oils?

Answer 35

Margarine is manufactured from vegetable oils by polymerisation.

Question 36

How do immiscible liquids, like oil and water, form emulsions?

Answer 36

They both have hydrophobic and hydrophilic ends and they attract to each other.

Question 37

What do we call the splitting up of fats using hydroxides?

Answer 37

The splitting up of fats using hydroxides is saponification.

Question 38

Explain the advantages of using low-temperature washing.

Answer 38

The advantages of using low-temperature washing is that it saves money on electricty and does not damage the clothes as much.

Question 39

Describe a detergent molecule.

Answer 39

Detergent molecules have a hydrophilic and hydrophobic ends.

Question 40

How does dry cleaning clean our clothes?

Answer 40

Dry cleaning cleans our clothes by using solvents that are not water and the dirt particles attach themsleves to the solvent and are removed.

Question 41

What kind of stains do dry-cleaning solvents act on?

Answer 41

Dry-cleaning solvents act on stains insoluble in water.

Question 42

What does the data on a washing powder packet tell you?

Answer 42

The temperature that you should use, the length of wash and the ingredients.

Question 43

Name the 5 ingredients in soap powder.

Answer 43

1. active ingredient 2. bleach 3. optical brightners 4. water softeners 5. enzymes