Types of Chemical Reactions (OCR GCSE Combined Science A (Gateway): Chemistry): Exam Questions

Exam code: J250

1 hour34 questions
11 mark

What is the name of the gas made when zinc carbonate reacts with hydrochloric acid?

  • Carbon dioxide

  • Chlorine

  • Hydrogen

  • Oxygen

21 mark

Which of these pH values shows the pH of a strong acid?

  • 1

  • 5

  • 7

  • 10

31 mark

What is the name of the gas made when magnesium reacts with sulfuric acid?

  • Carbon dioxide

  • Carbon monoxide

  • Hydrogen

  • Oxygen

41 mark

Calcium reacts with hydrochloric acid to form the salt, calcium chloride and another product. 

calcium  +   hydrochloric acid            →         calcium chloride  + ___________

What is the unknown product?

  • Water 

  • Oxygen

  • Hydrogen

  • Carbon dioxide 

51 mark

A solution of hydrochloric acid is pH 2. The acid solution is diluted, and the pH is now 3.

By what factor is the acid solution diluted?

  • 5

  • 10

  • 100

  • 1000

11 mark

A student added some sulfuric acid gradually to a solution of ammonia until it was in excess.

What happens to the pH during this reaction?

 

pH of ammonia at start

pH after addition of excess sulfuric acid 

A

11

7

B

7

13

C

11

2

D

3

8

    2
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    1 mark

    What is the ionic equation for neutralisation?

    • 2H(aq) + OH(aq)   →    H2O (l)

    • H(aq) + OH(aq)   →    H2O (aq)

    • H(aq) + OH(aq)   →    H2O (l)

    • 2H2 + O2    →       2H2O

    31 mark

    Zinc is extracted from zinc oxide by reduction.

    zinc oxide + carbon   →    zinc + carbon dioxide 

    Which element acts a reducing agent during this process?

    • Hydrogen

    • Oxygen

    • Carbon

    • Zinc 

    41 mark

    Sodium hydroxide reacts with sulfuric acid. 

    __NaOH + __H2SO4         →          __Na2SO4   +    __H2O

    Which numbers correctly balance the equation?

    • 1, 2, 2, 1

    • 2, 2, 1, 2

    • 2, 1, 1, 2 

    • 1, 1, 2, 2

    51 mark

    Sodium hydroxide reacts with hydrochloric acid. Sodium chloride and water are made.

    What is the name of this type of reaction?

    • Neutralisation

    • Oxidation

    • Reduction

    • Thermal decomposition

    61 mark

    Neutralisation occurs when acids react with alkalis.

    What is the ionic equation for neutralisation?

    • H+ + OH → H2O

    • H- + OH+ → H2O

    • H+ + OH+ → H2O

    • H- + OH → H2O

    71 mark

    Look at the equation.

    CH4 + 2O2 → CO2 + 2H2O

    Which substance is oxidised in this reaction?

    • CH4

    • CO2

    • H2O

    • O2

    81 mark

    Look at the equation.

    CH4 + 2O2 → CO2 + 2H2O

    Which substance is the oxidising agent in this reaction?

    • CH4

    • CO2

    • H2O

    • O2

    91 mark

    A student measures the pH of an acid and an alkali.

    He adds magnesium metal to the acid and to the alkali.

    What results should he expect?

    Acid

    Alkali

     

    pH

    Reaction with magnesium

    pH

    Reaction with magnesium

    A

    Below 7

    No reaction

    Above 7

    Magnesium fizzes

    B

    Below 7

    Magnesium fizzes

    Above 7

    No reaction

    C

    Above 7

    Magnesium fizzes

    Above 7

    No reaction

    D

    Above 7

    No reaction

    Above 7

    Magnesium fizzes

      101 mark

      Which equation represents neutralisation?

      • 2H+ → H2

      • H2O → H+ + OH-

      • H+ + OH- → H2O

      • 2OH- → O2 + H2

      111 mark

      Magnesium reacts with copper oxide.

      Magnesium oxide and copper are made.

      magnesium + copper oxide → magnesium oxide + copper

      Which substance is the reducing agent?

      • Copper

      • Copper oxide

      • Magnesium

      • Magnesium oxide

      121 mark

      Magnesium powder reacts with copper(II) oxide. Magnesium oxide and copper are made.

      Mg + CuO → MgO + Cu

      Which substance is the reducing agent?

      • Magnesium

      • Copper oxide

      • Magnesium oxide

      • Copper

      131 mark

      Higher Only

      The equation shows a reaction that involves both oxidation and reduction.

      Fe2O3 + 2Al → Al2O3 + 2Fe

      Which statement about reduction is correct?

      • The gain of oxygen and the gain of electrons by a substance

      • The gain of oxygen and the loss of electrons by a substance

      • The loss of oxygen and the gain of electrons by a substance

      • The loss of oxygen and the loss of electrons by a substance

      141 mark

      Which equation represents neutralisation?

      • 4H+ → 2H2

      • H2O → 2H+ + O2–

      • H+ + OH → H2O

      • O2 + H2 → H2O + O2–

      151 mark

      Nitrogen monoxide, NO, can be oxidised to form nitrogen dioxide, NO2.

      2NO + O2 → 2NO2

      What is the oxidising agent in this reaction?

      • nitrogen

      • nitrogen dioxide

      • nitrogen monoxide

      • oxygen

      1
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      1 mark

      A solution of sulfuric acid with a pH of 4 has a hydrogen ion concentration of 1 x 10-4 mol/dm3.

      Another acid has a hydrogen ion concentration of 1 x 10-6 mol/dm3.

      What is the pH of this acid?

      • 2

      • 3

      • 5

      • 6

      21 mark

      A reaction took place between iron sulfate and magnesium. 

      iron(II) sulfate + magnesium  →    magnesium sulfate + iron 

      Which species has been oxidised?

      • Iron

      • Magnesium

      • Sulfur

      • None of the above 

      31 mark

      A displacement reaction occurs between zinc and copper chloride.

      Which half equation correctly shows the change that zinc undergoes? 

      • Zn2+(aq) + 2e-  →    Zn (s)

      • Zn (s) + 2e-  →    Zn2+ (aq)

      • Zn2+ (aq)  → Zn (s) + 2e-

      • Zn (s)  →    Zn2+ (aq) + 2e-

      4
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      1 mark

      Higher Only

      A student investigates some acids.

      She has a solution of hydrochloric acid of concentration 0.01 mol / dm3.

      This solution has a pH of 2.

      She increases the concentration of hydrochloric acid from 0.01 mol / dm3 to 0.1 mol / dm3.

      What is the pH of this new solution?

      • 0

      • 1

      • 3

      • 12

      51 mark

      Which statement about an oxidising agent is correct?

      • It gains oxygen in a reaction.

      • It is oxidised in a reaction.

      • It is reduced in a reaction.

      • It loses electrons in a reaction.

      61 mark

      This is the balanced symbol equation for the reaction of copper oxide with carbon.

      2CuO + C → 2Cu + CO2

      What happens to the copper oxide in this reaction?

      • It is neutralised.

      • It is oxidised.

      • It is reduced.

      • It is thermally decomposed.