C6.1

Question 1

1. What does chemical synthesis provide?

Answer 1

Food additives: like preservatives, colourings, flavourings
Fertilisers: made of ammonia
Dyestuffs, paints, pigments
Pharmaceuticals: drugs

Question 2

2. What does the term ‘scale’ mean in terms of chemical synthesis in industry and in laboratories?

Answer 2

-large/small scale chemical production

Question 3

2. What is an example of chemical synthesis on a large scale?

Answer 3

-sulfuric acid for fertiliser and car batteries

Question 4

2. What is an example of chemical synthesis on a small scale?

Answer 4

-pharmaceuticals

Question 5

2. What are examples of sectors in the chemical industry?

Answer 5

• pharmaceuticals (largest sector)
• toiletries and cleaning
• plastic and rubber
• paints
• dyes
• fertilisers

Question 6

2. What contribution do sectors of the chemical industry have?

Answer 6

• economic contribution

- lots of jobs

Question 7

7. What states can pure acidic compounds be?

Answer 7

-solid, liquid, gas

Question 8

7. What are examples of SOLID pure acidic compounds?

Answer 8

-citric and tartaric acids

Question 9

7. What are examples of LIQUID pure acidic compounds?

Answer 9

-sulfuric, nitric and ethanoic acids

Question 10

7. What are examples of GAS pure acidic compounds?

Answer 10

-hydrogen chloride

Question 11

8. What are examples of common alkalis?

Answer 11

-the hydroxides of sodium, potassium and calcium

Question 12

9. What is the pH scale?

Answer 12

-a sliding scale from very strong acid (pH 0), to a very strong alkali (pH 14)

Question 13

9. What different pHs can a substance have

Answer 13

-acid (0), neutral (7), alkali (14)

Question 14

10. What is used to determine pH?

Answer 14

-indicators and pH metres

Question 15

10. What is the most accurate way of measuring pH?

Answer 15

-pH meters are more accurate then indicators

Question 16

10. What are examples of indicators and pH metres used to determine pH?

Answer 16

-litmus paper, universal indicator and pH meters

Question 17

10. What are indicators?

Answer 17

-a dye that changes colour if it’s above or below a certain pH

Question 18

10. What is litmus paper?

Answer 18

• determines if solution acid or alkaline
• red if acidic
• blue if alkaline

Question 19

10. What is Universal indicator?

Answer 19

• combination of dyes used to estimate the pH
• red= acid
• green=neutral
• purple= alkali

Question 20

10. What is a pH meter?

Answer 20

• gives more accurate readings of pH

- a probe dipped in the substance and a meter gives pH reading

Question 21

11. What are the reactions of acids that produce salts?

Answer 21

Acid + Alkali → Salt + Water (neutralisation reaction)
Acid + Metal → Salt + Hydrogen
Acid + Metal Oxide → Salt + Water (neutralisation reaction)
Acid + Metal Hydroxide → Salt + Water (neutralisation reaction)
Acid + Metal Carbonate → Salt + Water + carbon dioxide

Question 22

11. What is an acid?

Answer 22

-any substance with a pH of less than 7

Question 23

11. What is an alkali?

Answer 23

-any substance with a pH of more than 7

Question 24

11. What do an ACID + ALKALI make?

Answer 24

Salt + Water

neutralisation reaction

Question 25

11. What do an ACID + METAL make?

Answer 25

Salt + Hydrogen

Question 26

11. What do an ACID + METAL OXIDE make?

Answer 26

Salt + Water

Question 27

11. What do an ACID + METAL HYDROXIDE make?

Answer 27

Salt + Water

Question 28

11. What do an ACID + METAL CARBONATE make?

Answer 28

Salt + Water + carbon dioxide

Question 29

17. What is a neutralisation reaction?

Answer 29

-the reaction of an acid with an alkali to form a salt

Question 30

17. What is the general equation for a neutralisation reaction?

Answer 30

Acid + Alkali → Salt + Water

Question 31

17. What is the general equation for a neutralisation reaction in terms of ions?

Answer 31

H+(aq) + H-(aq) → H2O(l)

Question 32

18. What do that acidic compounds produce when they dissolve in water?

Answer 32

-aqueous hydrogen ions, H+ (aq)

Question 33

19. What do that alkaline compounds produce when they dissolve in water?

Answer 33

-aqueous hydroxide ions, OH–(aq)

Question 34

22. What is the general equation for a neutralisation reaction in terms of ions?

Answer 34

H+(aq) + H-(aq) → H2O(l)

Question 35

22. What happens to ions in a neutralisation reaction?

Answer 35

-the hydrogen ions from the acid react with hydroxide ions from the alkali to make water

Question 36

23. What does the term ENDOTHERMIC mean?

Answer 36

- in an endothermic reaction, energy is taken from the surroundings - energy is usually in form of heat= temperature increases

Question 37

23. What does the term EXOTHERMIC mean?

Answer 37

- in an exothermic reaction, energy is given to the surroundings - energy is usually in form of heat= temperature decreases

Question 38

23. What is an example of an endothermic reaction?

Answer 38

-photosynthesis

Question 39

23. What is an example of an exothermic reaction?

Answer 39

- fuels burning | - neutralisation reactions

Question 40

24. What do energy level diagrams show?

Answer 40

-the energy levels of products and reactants in a reaction

Question 41

24. How do you identify an endothermic reaction from an energy level diagram?

Answer 41

-products higher energy than reactants

Question 42

24. How do you identify an exothermic reaction from an energy level diagram?

Answer 42

-reactants higher energy than products

Question 43

24. What does the difference in height in energy level diagrams show?

Answer 43

- endothermic= energy taken in | - exothermic= energy given out

Question 44

25. What is the importance of the energy change during a reaction to the management and control of a chemical reaction (in the chemical industry) in EXOTHERMIC reactions?

Answer 44

- heat produced needs to be removed or reaction mixture temperature will increase - temp increase= increase rate of reaction= temp increase - temp increase= reactants/ products= gases= increase pressure= explosion

Question 45

25. What is the importance of the energy change during a reaction to the management and control of a chemical reaction (in the chemical industry) in ENDOTHERMIC reactions?

Answer 45

-heat needs to be added or reaction mixture temperature will decrease =decrease rate of reaction/ freeze mixture =stop process/damage equipment