Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Principles of Chemistry
991 practice questions
Topics covered
- States of Matter102 practice questions
- Elements, Compounds and Mixtures69 practice questions
- Atomic Structure108 practice questions
- The Periodic Table103 practice questions
- Chemical Formulae, Equations and Calculations Part 119 practice questions
- Chemical Formulae, Equations and Calculations Part 2144 practice questions
- Ionic Bonding143 practice questions
- Covalent Bonding68 practice questions
- Metallic Bonding19 practice questions
- Electrolysis198 practice questions
Practice questions
151–160 of 161 · Hard
Question 151
2 marks · Hard
Answer and see the solution →An aqueous solution of zinc sulfate is electrolysed using inert electrodes.
State whether hydrogen or zinc is produced at the cathode. Explain your answer using the reactivity series.
Question 152
5 marks · Hard
Answer and see the solution →A student electrolyses separate aqueous solutions containing different anions using inert electrodes.
(a)[1 mark]State which ion produces oxygen gas at the anode when an aqueous solution of sodium sulfate is electrolysed.
(b)[2 marks]Explain why oxygen is produced at the anode during this electrolysis and not another gas.
(c)[2 marks]During the electrolysis of aqueous sodium chloride with inert electrodes, state the product formed at the anode. Explain your answer.
Question 153
2 marks · Hard
Answer and see the solution →Predict the products formed at the electrodes when an aqueous solution of copper(II) bromide is electrolysed using inert electrodes.
State the product formed at:
(a)[1 mark]the cathode
(b)[1 mark]the anode
Question 154
2 marks · Hard
Answer and see the solution →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.
Question 155
5 marks · Hard
Answer and see the solution →A student investigates the electrical conductivity of three white solids: compound A, compound B and compound C. The student tests each substance (i) as a solid, (ii) after dissolving it in water, and (iii) after melting it. The observations are recorded below:
Conductivity results for three compounds Substance Solid Aqueous solution Molten Compound A Does not conduct Does not conduct Does not conduct Compound B Does not conduct Conducts Conducts Compound C Does not conduct Does not conduct Conducts (a)[4 marks]For each compound (A, B and C), state whether it is ionic, covalent (non-electrolyte), or another type. Give a reason for each answer.
(b)[1 mark]Suggest a familiar example of a substance that would behave in the same way as compound A.
Question 156
2 marks · Hard
Answer and see the solution →A student is investigating whether a white crystalline solid is an ionic compound or a covalent compound. The student finds that the solid does not conduct electricity, and that dissolving the solid in water still does not allow the solution to conduct electricity. State what type of compound the solid is and explain your reasoning.
Question 157
7 marks · Hard
Answer and see the solution →A science teacher asks students to compare what happens at the cathode during the electrolysis of sodium chloride solution and copper(II) sulfate solution, both using inert electrodes.
(a)[3 marks]Explain why the solution around the cathode becomes alkaline during the electrolysis of sodium chloride solution.
(b)[2 marks]Explain why copper is deposited at the cathode instead of hydrogen during the electrolysis of copper(II) sulfate solution using inert electrodes.
(c)[2 marks]In both electrolysis experiments above, water is present in solution. State one difference in the effect of prolonged electrolysis on the composition of the solution in each case, and explain your answer using the relevant ions.
Question 158
7 marks · Hard
Answer and see the solution →A student investigates the products formed at the cathode when electrolysing sodium chloride solution and copper(II) sulfate solution, each with inert electrodes.
(a)[1 mark]State the product formed at the cathode during the electrolysis of sodium chloride solution using inert electrodes.
(b)[2 marks]Explain why hydrogen, not sodium, is produced at the cathode during the electrolysis of sodium chloride solution.
(c)[1 mark]State the product formed at the cathode during the electrolysis of copper(II) sulfate solution using inert electrodes.
(d)[2 marks]Explain why copper is deposited at the cathode during the electrolysis of copper(II) sulfate solution with inert electrodes.
(e)[1 mark]In both experiments, describe one observation that could be made at the cathode, and explain how it relates to the product formed.
Question 159
7 marks · Hard
Answer and see the solution →Electrolysis of sodium chloride solution and copper(II) sulfate solution can be represented by balanced half-equations.
(a)[2 marks]Write a balanced half-equation for the reaction at the cathode during electrolysis of sodium chloride solution.
(b)[1 mark]Write a balanced half-equation for the reaction at the anode during electrolysis of sodium chloride solution.
(c)[2 marks]Write a balanced half-equation for the reaction at the cathode during electrolysis of copper(II) sulfate solution using inert electrodes.
(d)[2 marks]Write a balanced half-equation for the reaction at the anode during electrolysis of copper(II) sulfate solution using inert electrodes.
Question 160
9 marks · Hard
Answer and see the solution →Magnesium and chlorine can combine in different ways to form compounds. Ammonia is another important compound formed from non-metals.
(a)[2 marks]Describe how magnesium and chlorine atoms form ions and the charges of these ions.
(b)[2 marks]Explain what holds the ions together in the compound magnesium chloride.
(c)[2 marks]Define a covalent bond and describe how it forms specifically in an ammonia (NH₃) molecule.
(d)[2 marks]Compare the type of particles present in solid magnesium chloride and in ammonia. State one reason for your answer.
(e)[1 mark]State whether you would expect solid magnesium chloride or ammonia to have a higher melting point. Explain your answer.