Week 3 part 2

Question 1

What do acids do in water?

Answer 1

• Produce protons (H+ ions)
• ionise in aqueous solutions
• Produce hydrogen gas

Question 2

What do strong acids to in water?

Answer 2

• Ionise completely

- All acid particles dissociate (break down) to release H+ ions

Question 3

What do weak acids do in water?

Answer 3

• Don’t fully ionise in a solution

- Only a small amount of acid particles dissociate to release H+ ions

Question 4

What are the notes on acids?

Answer 4

• Reactions of acids involve H+ ions reacting with other substances. If the concentrations of H+ ions is higher, the rate of reaction will be faster.
• The reactions with weak acids is reversible

Question 5

What is the link between concentration of H+ ions and the pH value?

Answer 5

As the pH value increases by 1 the concentration of H+ ions is divided by 10. Measured in mol/dm^3
e.g. pH 1 = 10 mol/dm^3
pH 2 = 1 mol/dm^3
pH 3 = 0.1 mol/dm^3

Question 6

What does acid strength tell you?

Answer 6

• What proportion of the acid molecules ionise water

Question 7

What does concentration tell you?

Answer 7

• How much acid there is in a certain volume of water

Question 8

Give a word equation for a metal oxide add acid?

Answer 8

Acid + Metal Oxide = Salt + Water

Question 9

Give a word equation for a metal hydroxide add acid?

Answer 9

Acid + Metal hydroxide = Salt + Water

Question 10

Give a word equation for a metal carbonate add acid?

Answer 10

Acid + Metal Carbonate = Salt + water + carbon dioxide

Question 11

Carry out a neutralisation practical involving copper oxide and sulphuric acid?

Answer 11

1) Measure out 40 cm^3 of sulphuric acid in measuring cylinder. Pour the H2SO4 into a beaker.
2) Heat the H2SO4 to make the reaction go faster using a tripod, gauze and bunsen burner for 30 seconds.
3) Take off the heat and add copper oxide. The CuO is added in excess to assure that the acid is fully neutralised. Add a little bit first and mix, then add another spatula for the excess. You’ll know that you’ve added excess when you see black unreacted copper oxide.
4) Use filtration to get rid of the insoluble copper oxide
5) Using a tripod, gauze, bunsen burner and beaker full of water setup, put the copper sulphate(L) into an evaporating dish to evaporate the water. (water bath)