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Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit

Principles of Chemistry

991 practice questions

Topics covered

Practice questions

951–960 of 991

  1. Question 951

    2 marks · Easy

    The results of an experiment are shown below:

    Conductivity Results
    SubstanceState TestedConducts Electricity?
    Magnesium chlorideSolidNo
    Magnesium chlorideMoltenYes
    EthanolLiquidNo

    Identify whether each substance is ionic, covalent, or a non-electrolyte. Give a reason for your answer in each case.

    (a)

    Magnesium chloride:

    [1 mark]
    (b)

    Ethanol:

    [1 mark]
    Answer and see the solution →
  2. Question 952

    2 marks · Normal

    A student wants to know whether glucose (C6H12O6) is an electrolyte, an ionic compound, or a covalent compound. They attempt to pass an electric current through both solid glucose and glucose dissolved in water, but the bulb does not light up in either case.

    State what type of substance glucose is and give a reason based on the results of the experiment.

    Answer and see the solution →
  3. Question 953

    4 marks · Normal

    Two students investigate the ability of different substances to conduct electricity using the apparatus below.

    (a)

    Complete the table below by identifying whether each substance is likely to conduct electricity or not in the form stated.

    SubstanceStateWill it conduct electricity? (Yes/No)
    Sodium chlorideMolten
    Sucrose (C12H22O11)Aqueous solution
    [2 marks]
    (b)

    Explain why one of these substances does not conduct electricity in the given state.

    [2 marks]
    Answer and see the solution →
  4. Question 954

    3 marks · Normal

    Water is often used as the solvent in electrolysis experiments. Pure water conducts electricity only very weakly, but when a small amount of sodium chloride is added, it conducts electricity much better.

    Explain why pure water is a poor conductor of electricity and why adding sodium chloride increases the conductivity so much.

    Answer and see the solution →
  5. Question 955

    4 marks · Normal

    The table below shows results from an experiment where a student measured the volume of oxygen gas produces at the anode when different substances are electrolysed:

    Results of electrolysis
    Substance (aq)Bulb lights?Volume of O2 at anode (cm³)
    Sodium sulfateYes18.5
    Copper(II) sulfateYes17.8
    SugarNo0
    EthanolNo0
    (a)

    Identify which substances are electrolytes and which are non-electrolytes. Explain your choices.

    [2 marks]
    (b)

    State what this experiment shows about the type of bonding in sugar and ethanol.

    [2 marks]
    Answer and see the solution →
  6. Question 956

    1 mark · Normal

    The student sets up an apparatus to test substance X for electrical conductivity. The bulb stays off, and even after substance X is dissolved in water, there is still no current. What does this suggest about substance X?

    1. A.It is an ionic compound that conducts electricity when solid.
    2. B.It is a covalent compound that forms ions in water.
    3. C.It is a non-electrolyte and does not produce ions in solution.
    4. D.It is an acid and must form ions in solution.
    Answer and check →
  7. Question 957

    2 marks · Normal

    Explain why potassium iodide (KI) will conduct electricity when molten but not as a solid.

    Answer and see the solution →
  8. Question 958

    4 marks · Normal

    You are given a white solid (substance Y) that is soluble in water. You need to determine whether it is an ionic compound, a covalent compound, or a non-electrolyte.

    (a)

    Describe an experiment you could do to determine the type of substance.

    [2 marks]
    (b)

    State what you would observe if substance Y is an ionic compound and explain your answer.

    [2 marks]
    Answer and see the solution →
  9. Question 959

    3 marks · Normal

    A student wants to find out whether substance X is an ionic compound, a covalent compound (non-electrolyte), or an acid using an experiment. She sets up the following experiment in which two carbon electrodes are placed in a solution of substance X, connected to a power supply and a bulb, as shown in the diagram:

    Apparatus: beaker (solution of X), test tube (carbon electrode), test tube (carbon electrode)carbon electrodecarbon electrodesolution of X
    Apparatus for testing conductivity.

    In three separate experiments she uses:

    TestSubstance in solutionObservation
    AX dissolved in waterBulb does not light up
    BMolten XBulb lights up
    CAqueous acidBulb lights up

    Using the data above, calculate whether substance X is ionic, covalent (non-electrolyte), or an acid. Explain your reasoning.

    Answer and see the solution →
  10. Question 960

    2 marks · Hard

    A student tries to electrolyse solid iodine and observes no current flows through the circuit. The student then dissolves the iodine in water and tries again, but the bulb still does not light. State and explain what these results show about the electrical properties and bonding type of iodine.

    Answer and see the solution →