Unit 1-Neutralisation

Question 1

What is a neutralisation reaction?

Answer 1

Neutralisation is the reaction of an acid with a base that results in the pH moving towards 7.

Neutralisation also moves the pH of an alkali down towards seven.

Question 2

What is the general equation when an acid is neutralised by an alkali (metal hydroxide)?

Answer 2

Acid + Alkali → Metal Salt + Water

Question 3

What is the general equation when an acid is neutralised by a metal oxide?

Answer 3

Acid + Metal oxide → Metal Salt + Water

Question 4

What is the general equation when an acid is neutralised by a metal carbonate?

Answer 4

Acid + Metal Carbonate → Metal Salt + Water + Carbon Dioxide

Question 5

How do you name the salt formed in a neutralisation reaction?

Answer 5

the metal ion from the alkali (or base) replaces the hydrogen ion from the acid - (alkali to front, acid to back). For example:

Hydrochloric Acid + Sodium Hydroxide → Sodium Chloride + Water

Hydrochloric acid…chloride

Sulfuric acid…sulfate

Nitric acid…nitrate

Question 6

What word is used to describe ions that are present during the reaction but are unchanged by the reaction, and so are present in the same state on both sides of the equation?

Answer 6

Spectator ions

Question 7

How would the following ionic equation be rewritten omitting the spectator ions?

H⁺_(aq) + Cl^-_(aq) + Na⁺_(aq) + OH^-_(aq) → Na⁺_(aq) + Cl^-_(aq) + H₂O_(l)

Answer 7

H⁺_(aq) + OH^-_(aq) → H₂O_(l)

Question 8

How would the following ionic equation be rewritten omitting the spectator ions?

2H⁺_(aq) + 2NO₃^-_(aq) + Ca²⁺_(aq) + CO₃^2-_(aq) → Ca²⁺_(aq) + 2NO₃^-_(aq) + H₂O_(l) + CO_2(g)

Answer 8

2H⁺_(aq) + CO₃^2-_(aq) → H₂O_{(l) +} CO_2(g)

Question 9

Reactions can be represented using ionic equations.

A: H⁺_(aq) + OH^-_(aq) → H₂O_(l)

B: 2H₂O_(l) + O_2(g) + 4e^{<span>-</span>} → 4OH^-_(aq)

C: 2H⁺_(aq) + CO₃^2-_(aq) → H₂O_(l) + CO_2(g)

D: SO_2(g) + H₂O_(l) → 2H⁺_(aq) + SO₃^2-_(aq)

E: NH₄⁺_(aq) + OH^-_(aq) → NH_3(g) + H₂O_(l)

Identify the two ionic equations that show the neutralisation of an acid.

Answer 9

A: H⁺_(aq) + OH^-_(aq) → H₂O_(l)

C: 2H⁺_(aq) + CO₃^2-_(aq) → H₂O_(l) + CO_2(g)

Question 10

What is the purpose of a titration reaction?

Answer 10

This technique is commonly used in neutralisation reactions and to calculate an unknown concentration (of either the acid or alkali).

Question 11

What are these four pieces of apparatus used to carry out a titration called?

Answer 11

Burette, Conical flask, pipette filler and pipette

Question 12

Which titration results should be used to calculate an average volume used?

Answer 12

Titration 2 and 3. They are concordant (within 0·2 cm³)

Titration 1 is considered a rough titre. This allows you to know roughly how much will be needed.