Organic Chemistry (OCR Gateway GCSE Chemistry)

Exam Questions

11 mark

Look at the displayed formula of an organic compound.

q1-paper-2-specimen-2016-ocr-gcse-chem

What is the name of this compound?

  • Butanoic acid

  • Butanol

  • Propanoic acid

  • Propanol

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21 mark

DNA is a condensation polymer made from monomers called nucleotides.

How many different nucleotides are used to make DNA molecules?

  • 2

  • 3

  • 4

  • 5

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31 mark

What is the name of the process that converts large alkane molecules into smaller alkane molecules?

  • Cracking

  • Fractional distillation

  • Hydrogenation

  • Polymerisation

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41 mark

Which displayed formula shows an alkene?

q4-paper-2-june-2018-ocr-gcse-chem

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    51 mark

    A student bubbles ethene gas into bromine water.

    What is observed?

    • Colour change from blue to colourless

    • Colour change from colourless to orange

    • Colour change from orange to colourless

    • Orange precipitate is made

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    61 mark

    What is the formula of the functional group in alcohols?

    • −CH3

    • −COOH

    • −CO2

    • −OH

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    71 mark

    What is the displayed formula of ethanol?

    • screenshot-2024-11-06-123322

    • screenshot-2024-11-06-123538

    • screenshot-2024-11-06-123627

    • screenshot-2024-11-06-123712

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    81 mark

    Methane is a hydrocarbon.


    Which substance cannot be produced when methane burns in air?

    • Carbon

    • Carbon dioxide

    • Hydrogen

    • Water

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    91 mark

    Crude oil is a resource that is being made extremely slowly.


    Which word describes a resource that is being made extremely slowly?

    • Finite

    • Hydrocarbon

    • Non‐renewable

    • Petrochemical

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    101 mark

    Which of these homologous series can form addition polymers?

    • Alcohols and carboxylic acids

    • Alkenes and alkanes

    • Alkenes only

    • Carboxylic acids only

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    11 mark

    Heptane is an alkane with seven carbons.

    What is the chemical formula of heptane?

    • C7H10

    • C7H12

    • C7H14

    • C7H16

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    21 mark

    The complete combustion of pentane, C5H12, takes place in the following unbalanced equation:

    _C5H12   +   _O2 →   _CO2   +  _H2O

    What numbers will balance the reaction?

    • 1,4,5,3

    • 1,8,5,6

    • 2,8,5,6

    • 2,4,5,6

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    31 mark

    Which of the following molecules is an alkene?

    • C6H10

    • C4H10

    • C5H10

    • C6H14

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    41 mark

    The following molecule can undergo addition polymerisation. 

    6-2_q4_1-ocr-gcse-chemistry-mcq-

    What it the correct repeat unit?.6-2-q4_2-ocr-gcse-chemistry-mcq

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      51 mark

      Which of the following is not true about DNA?

      • The structure is a double helix

      • DNA is made from nucleotides

      • DNA is made from two polymer chains

      • The monomers that form DNA are amino acids

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      61 mark

      The structure of a polymer is shown below.

      6-2-q7_1-ocr-gcse-chemistry-mcq

      What is the correct monomer?6-2-q7_2-ocr-gcse-chemistry-mcq



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        7
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        1 mark

        Hydrogen fuel cells can be used to power trains.

        Why could people refer to the hydrogen fuel cell trains as the 'new' steam trains?

        • The hydrogen used is extracted from fossil fuels

        • The hydrogen fuel cell trains are slower than diesel trains

        • The reaction produces water that can be released as steam

        • The reaction in the fuel cell is a combustion reaction

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        81 mark

        Hydrogen fuel cells are often used instead of rechargeable batteries in spacecraft.

        Which of the following is not an advantage of using hydrogen fuel cells in spacecraft?

        • Water is the only product made in the reaction

        • The fuel cells have no moving parts so are easy to maintain

        • Hydrogen and oxygen are easily made by electrolysis of water

        • Hydrogen fuel cells are cheap

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        91 mark

        Which molecule can be cracked to produce hexane, C6H14?

        • C4H8

        • C4H10

        • C6H12

        • C10H22

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        101 mark

        Crude oil is a mixture of hydrocarbons.

        Crude oil is separated into useful fractions.

        Which of these mixtures of substances could be in a fraction from crude oil?

        • C2H4, C4H10, C4H10O

        • C2H4, C2H3Br, C4H10

        • C2H6, C3H8, C4H10

        • C2H6, C2H3Br, C4H10O

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        111 mark

        What happens to the potential difference of a chemical cell once the reactants are used up?

        • It decreases

        • It increases

        • It starts and finishes at 0 V

        • It stays the same

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        121 mark

        Crude oil is separated into fractions by fractional distillation.

        Look at the diagram of the fractions made in fractional distillation.

        q7-paper-2-nov-2020-ocr-gcse-chem

        Which of these fractions has the lowest boiling point?

        • Bitumen

        • Diesel oil

        • Gases

        • Petrol

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        131 mark

        What type of reaction takes place between an alkene and hydrogen?

        • Addition

        • Dehydration

        • Neutralisation

        • Thermal decomposition

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        141 mark

        DNA molecules are polymers.

        What is the name of the monomers that make up DNA molecules?

        • Amino acids

        • Carbohydrates

        • Nucleotides

        • Proteins

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        151 mark

        Which of the following are the first four members of the homologous series of alcohols?

        • CH4, C2H6, C3H8, C4H10

        • CH3OH, C2H5OH, C3H7OH, C4H9OH

        • HCOOH, CH3COOH, C2H5COOH, C3H7COOH

        • C2H4, C3H6, C4H8, C5H10

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        161 mark

        Look at the displayed formula of the monomer butene.

        q11-paper-2-june-2018-ocr-gcse-chem

        What is the formula of the polymer formed from butene?

        q11-1-paper-2-june-2018-ocr-gcse-chem

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          171 mark

          The bar chart shows the amount of some fractions made from 100 tonnes of crude oil by fractional distillation.

          It also shows the amount of each fraction needed for everyday uses.

          q11-paper-2-specimen-2016-ocr-gcse-chem

          Cracking converts large molecules into smaller more useful molecules to make the supply match the demand.

          Which fractions are most likely to be cracked to make the supply match the demand?

          • Gas oil and fuel oil

          • Gas oil and petrol

          • Naphtha, paraffin and fuel oil

          • Petrol and gases

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          181 mark

          What is the formula of the product in this equation?

          q10-paper-2-june-2018-ocr-gcse-chem

          • C2H2Br

          • C3Br4

          • C2H3Br

          • C2H4Br2

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          191 mark

          Which displayed formula includes the functional group of an alcohol?

          q15-paper-2-specimen-2016-ocr-gcse-chem


















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            201 mark

            What is the general formula of the fractions produced by the fractional distillation of crude oil?

            • CnH2n

            • CnH2n+2

            • C2H2n+1OH

            • C2n+2H2

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            211 mark

            Which displayed formula shows butanol?

            q5-paper-4-june-2019-ocr-gcse-chem

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              221 mark

              Higher Only

              Look at the equations for the reactions that happen at each side of a hydrogen‑oxygen fuel cell.

              Reaction 1: 2H2 (g) → 4H+ (aq) + 4e
              Reaction 2: 4H+ (aq) + O2 (g) + 4e→ 2H2O (g)

                Reaction 1 Reaction 2
              A Oxidation because electrons are gained Reduction because electrons are lost
              B Reduction because electrons are gained Reduction because electrons are gained
              C Oxidation because electrons are lost Reduction because electrons are gained
              D Oxidation because electrons are lost Oxidation because electrons are lost

              Which row of the table, A, B, C or D, is correct about reactions 1 and 2?

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                231 mark

                A student reacts a hydrocarbon with bromine water.

                The formula of the product is C3H6Br2.

                Which is the displayed formula of the hydrocarbon?

                q10-paper-4-nov-2020-ocr-gcse-chem

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                  241 mark

                  A student bubbles ethene gas into bromine water.

                  Which displayed formula shows the product of this reaction?

                  • ch2br2

                  • c2h4br2

                  • c2h3br

                  • 1-1-c2h4br2

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                  251 mark

                  Which of these homologous series can react together to form addition polymers?

                  • Alcohols and carboxylic acids

                  • Alkenes only

                  • Alkenes and alkanes

                  • Carboxylic acids only

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                  261 mark

                  A student heats compound X with acidified potassium manganate(VII) solution.

                  The product of the reaction is compound Y.

                  q14-paper-4-specimen-2016-ocr-gcse-chem

                  What is the colour change seen during this reaction?

                  • Colourless to orange

                  • Colourless to purple

                  • Orange to colourless

                  • Purple to colourless

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                  271 mark

                  What is the formula of the functional group in alcohols?

                  • −CH3

                  • −COOH

                  • −CO2

                  • −OH

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                  11 mark

                  Crude oil is separated into fractions by fractional distillation.

                  Look at the diagram of the fractions made in fractional distillation

                  q3-paper-4-nov-2020-ocr-gcse-chem

                  Which of these fractions has the strongest intermolecular forces?

                  • Bitumen

                  • Diesel oil

                  • Gases

                  • Kerosene

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                  21 mark

                  Look at the structure of glycine.

                  q7-paper-4-nov-2020-ocr-gcse-chem

                  Glycine is a monomer that reacts to form proteins.

                  Glycine contains two different functional groups that allow it to undergo polymerisation.

                  What are the two functional groups?

                  • −NH2 and −C=O

                  • −NH2 and −CH2

                  • −NH2 and −OH

                  • −NH2 and −COOH

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                  31 mark

                  Higher Only

                  Which statement explains why polyamides are condensation polymers?

                  • A molecule of water forms each time a hydroxyl link forms.

                  • A molecule of water forms each time an ester link forms.

                  • A molecule of water forms each time an amine group reacts with a carboxylic acid group.

                  • A molecule of water forms each time an alcohol group reacts with a carboxylic acid group.

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                  41 mark

                  Which fraction is collected at the top of the fractional distillation column?

                   

                  Melting point range (°C)

                  Boiling point range (°C)

                  A

                  –70 – –60

                  20 – 25

                  B

                  –50 – –40

                  30 – 50

                  C

                  0 – 20

                  100 – 120

                  D

                  20 – 40

                  130 – 160

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                    51 mark

                    What is the correct balanced equation for the combustion of hexane, C6H14?

                    • C6H14 + 13O2 → 6CO2 + 7H2O

                    • C6H14 + 6O2 → 6CO2 + 7H2O

                    • 2C6H14 + 19O2 → 12CO2 + 14H2O

                    • 2C6H14 + 26O2 → 12CO2 + 14H2O

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                    61 mark

                    Polyesters can be made by condensation polymerisation. Ethanediol can react with butanedioic acid (a carboxylic acid containing two -COOH groups) to make a polymer.

                    6-2-q5_1-ocr-gcse-chemistry-mcq

                    Which of the following is a correct repeat unit for this polymer?

                    6-2-q5_2-ocr-gcse-chemistry-mcq

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                    71 mark

                    Which of the following shows the product of the reaction between propene and bromine?

                    6-2-q11-ocr-gcse-chemistry-mcq

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                      81 mark

                      Ethene, C2H4, reacts with bromine, Br2, in an addition reaction.

                      Which is the balanced symbol equation for this reaction?

                      • C2H4 + Br2 → C2H3Br + HBr

                      • C2H4 + Br2 → C2H4Br2

                      • C2H4 + 2Br2 → C2Br4 + 2H2

                      • C2H4 + 2Br2 → C2H4Br4

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                      91 mark

                      A hydrogen-oxygen fuel cell produces electricity.

                      Hydrogen reacts with oxygen to produce water.

                      What is the equation for the reaction that happens at the anode?

                      • 2H2 (g) + O2 (g) → 2H2O (g)

                      • 4H+ (aq) + 4e- → 2H2 (g)

                      • 2H2 (g) → 4H+ (aq) + 4e-

                      • 4H+ (aq) + O2 (g) + 4e- → 2H2O (g)

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                      101 mark

                      Higher Only

                      Which pairs of molecules would react to form a polyester?

                      • q10-paper-4-june-2019-ocr-gcse-chem

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                      111 mark

                      Which statement about chemical cells is correct?

                      • They produce a voltage indefinitely.

                      • They produce a voltage once all of the reactants are used up.

                      • They produce a voltage until one of the reactants is completely used up.

                      • They produce a voltage until the reactants are partly used up.

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                      121 mark

                      Ethane is a very small hydrocarbon molecule.

                      Which row about ethane is correct?

                        Easy to ignite? Boiling point
                      A high
                      B x high
                      C low
                      D x low

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                        131 mark

                        Ethene, C2H4, reacts with bromine in an addition reaction.


                        What is the structural formula of the product?

                        • screenshot-2024-11-06-215709

                        • screenshot-2024-11-06-215713

                        • screenshot-2024-11-06-215717

                        • screenshot-2024-11-06-215723

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                        141 mark

                        What is the half equation for the reaction at the anode in a hydrogen/oxygen fuel cell?

                        • 2H2 + O2 → 2H2O

                        • 2H2 → 4H+ + 4e

                        • 4H+ + 4e→ 2H2

                        • 4H+ + O2 + 4e → 2H2O

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