IGCSEScienceEdexcelScience (Double Award) (Modular)Chemistry Unit 1Exam Questions2. Inorganic Chemistry: Part 1Acids, bases & salt preparations

Acids, bases & salt preparations (Edexcel IGCSE Science (Double Award) (Modular): Chemistry Unit 1): Exam Questions

Exam code: 4XSD1

57 mins9 questions
Easy
Medium
Hard
1
1 mark

A neutralisation reaction occurs between ammonia and sulfuric acid. 

How does the ammonia act in this reaction?

  • As a proton donor

  • As an electron acceptor

  • As a proton acceptor

  • As a neutron donor

Choose your answer

2
1 mark

The chemical equation for the preparation of lead(II) sulfate is written below. 

Pb(NO3)2  (___) + Na2SO4 (___) → PbSO4 (___) + 2NaNO3 (___)

What are the state symbols for each substance in this reaction? 

  • aq, aq, s, aq

  • aq, aq, s, s

  • s, aq, aq, s

  • s, aq, s, aq

Choose your answer

3
1 mark

A student making copper sulfate crystals used the method below.

Two labelled stages. Step 1 shows a beaker containing a dark solid labelled copper carbonate, with liquid labelled sulfuric acid being poured in from a container above. An arrow leads down to step 2, which shows the same beaker part filled with liquid and a smaller amount of the dark solid at the bottom, labelled unreacted copper carbonate.

Unreacted copper carbonate was left over as it had been added in excess.

What is the reason for adding it in excess and what would step 3 be of this method?

  • Reason: to produce a greater amount of salt crystals
    Step 3: filtration

  • Reason: to improve the colour intensity of the crystals
    Step 3: crystallisation

  • Reason: to ensure all the acid reacts
    Step 3: filtration

  • Reason: to increase the rate of reaction
    Step 3: evaporation

Choose your answer

4a
1 mark

Sulfuric acid can be used to make a soluble salt when reacted with a base. 

All acids contain the same ion. What is the formula of this ion?

  • H+

  • OH-

  • S2-

  • Na+

Choose your answer

4b
1 mark

Sulfuric acid reacts with copper(II) oxide to form a salt.  What is the name of the salt formed?

  • Copper(II) chloride

  • Copper(II) nitrate

  • Copper(II) sulfate

  • Copper(II) citrate

Choose your answer

4c
1 mark

The steps below show the method the student carried out to make the salt using the reactants in part b).

The steps shown are not in the correct order. 

 step J

 Leave the solution to cool  

 step K

 Filter the mixture and transfer the filtrate to an evaporating basin

 step L

 Add copper(II) oxide in excess

 step M

 Heat the acid 

 step N

 Evaporate the water until crystals appear

Write the steps in the correct order. 

Some have been completed for you. 

 first step

 

 

 

last step

M

 

 

 

J

How did you do?

4d
1 mark

Explain why the copper(II) oxide was added in excess to the sulfuric acid.

How did you do?

1a
8 marks

A student makes some magnesium nitrate crystals from magnesium oxide and dilute nitric acid. The equation for the reaction is

MgO (s) + 2HNO3 (aq) → Mg(NO3)2 (aq) + H2O (l)

i) Give the formula of each ion in magnesium nitrate.

......................................... and ......................................

[2]

ii) A student has a beaker containing dilute nitric acid. Describe a method that she could use to prepare a pure, dry sample of magnesium nitrate crystals from magnesium oxide.

[6]

How did you do?

1b
6 marks

Magnesium nitrate crystals contain water of crystallisation with the formula Mg(NO3)2.6H2O

i) Show by calculation that the relative formula mass of Mg(NO3)2.6H2O is 256.

[1]

ii) Show that the maximum mass of Mg(NO3)2.6H2O that could be made from 0.050 mol of nitric acid is about 6 g.

[3]

iii) The actual mass of crystals that the student obtains is 4.8 g. Calculate the percentage yield of Mg(NO3)2.6H2O in this experiment.

[2]

How did you do?

2a
4 marks

A student investigates the neutralisation reaction between sodium hydroxide and nitric acid. This is her method.

  • pour 20 cm3 of sodium hydroxide solution into a polystyrene cup

  • record the temperature of the sodium hydroxide solution

  • add 5 cm3 of dilute nitric acid to the cup

  • stir the mixture and record the highest temperature reached

  • add further 5 cm3 portions of dilute nitric acid, recording the highest temperature reached each time, until a total of 40 cm3 of acid has been added

i) Give a word equation for this neutralisation reaction.

[1]

ii) Explain why a polystyrene cup is used rather than a beaker.

[2]

iii) Give a safety precaution that the student should take when using sodium hydroxide solution.

[1]

How did you do?

2b
5 marks

The table shows the student’s results.

Total volume of acid in cm3

0

5

10

15

20

25

30

35

40

Temperature of reaction mixture in °C

20.5

22.5

24.4

26.4

28.5

28.3

27.5

26.7

26.0

i) Plot the results on the grid. Draw a straight line of best fit through the first five points and another straight line of best fit through the last four points. Make sure that the two lines cross.

[3]

An empty graph grid ruled in small squares. The x-axis is labelled total volume of acid in cm^3^ and runs from 0 to 40 in steps of 10. The y-axis is labelled temperature of reaction mixture in °C and runs from 20 to 30, labelled at 20, 25 and 30.

ii) The point where the lines cross shows

  • the volume of acid needed to exactly neutralise the alkali

  • the maximum temperature reached

Use your graph to determine these values.

volume of acid = ...................................................................... cm3 maximum temperature = ............................................... °C

[2]

How did you do?

3
1 mark

Which equation does not show the correct reaction of an acid? 

  • copper oxide + hydrochloric acid → copper chloride + water 

  • calcium carbonate + nitric acid → calcium nitrate + carbon dioxide

  • potassium hydroxide + sulfuric acid → potassium sulfate + water

  • zinc + sulfuric acid → zinc sulfate + hydrogen 

Choose your answer

1a
2 marks

This question is about salts.

Soluble salts can be prepared by the reaction between a metal oxide and an acid.

The equation for this type of reaction is:

metal oxide + acid → salt + water

i) State the name given to this type of reaction.

[1]

ii) State, in terms of protons, what happens in this reaction.

[1]

How did you do?

1b
8 marks

A student is given 50 cm3 of dilute sulfuric acid and a bottle of solid copper(II) carbonate.

i) Describe the method that the student should use to prepare a saturated solution of copper(II) sulfate.

In your answer, refer to the pieces of apparatus that the student should use.

[5]

ii) The student produces dry crystals of hydrated copper(II) sulfate from the saturated solution.

He calculates that 6.40 g of dry crystals should be formed.

The mass of dry crystals he actually obtains is 1.80 g less than he calculated.

Calculate the student’s percentage yield.

Give your answer to one decimal place.

percentage yield = .............................................. %

[3]

How did you do?

1c
5 marks

i) Gypsum is hydrated calcium sulfate.

A sample of gypsum contains 79% of calcium sulfate by mass.

Calculate the value of x in CaSO4.xH2O

[Mr of CaSO4 = 136 Mr of H2O = 18]

x = ..............................................

[3]

ii) Describe a test for calcium ions in the sample of gypsum.

[2]

How did you do?

2a
1 mark

An insoluble solid and dilute sulfuric acid can react to produce soluble salts. 

Copper, copper carbonate and copper oxide are insoluble solids. 

Which of these insoluble solids can be used to make a copper salt by reacting the solid with dilute sulfuric acid?

  • Copper and copper oxide only

  • Copper and copper carbonate only

  • Copper carbonate, copper and copper oxide

  • Copper carbonate and copper oxide only

Choose your answer

2b
2 marks

A student made crystals of magnesium nitrate using nitric acid and magnesium oxide. 

Give a balanced symbol equation for the reaction.

How did you do?

2c
3 marks

The method the student used to make magnesium nitrate crystals is below. 

a.

 Add nitric acid to a beaker

b.

 Warm the nitric acid

c.

 Add magnesium oxide to the beaker using a spatula

d.

 Stir the mixture

e.

 Repeat steps c and d until some magnesium oxide remains in the beaker

f.

 Filter the mixture 

g.

 Heat the filtrate to evaporate some solution until crystals start to form

h. 

 Leave the solution to finish crystallising 

Explain why each of the following steps was carried out:

Step b: ...........................................................................................................

Step e: ...........................................................................................................

Step f: ..........................................................................................................

How did you do?

2d
3 marks

A different student used magnesium carbonate and nitric acid to make magnesium nitrate. They wanted to make 11 g of magnesium nitrate.  The equation for the reaction is: 

MgCO3 + 2HNO3  →  Mg(NO3)2 + H2O + CO2

Calculate the mass of magnesium carbonate the student should react with dilute nitric acid to make 11.0 g of magnesium nitrate.

(Ar: H= 1; C = 12; O = 16; N = 14; Mg = 24)

How did you do?

2e
2 marks

The percentage yield of magnesium nitrate was 76.3%. 

Calculate the mass of magnesium nitrate the student actually produced. 

How did you do?