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
281–290 of 423 · Normal
Question 281
3 marks · Normal
Answer and see the solution →A student looks at two samples of different ionic compounds under a microscope. Sample A forms visible cube-shaped grains, but Sample B appears as a fine white powder and individual grains are not visible to the naked eye.
Using ideas about the arrangement of ions, calculate and explain how the crystalline property of ionic compounds is demonstrated in both samples.
Question 282
4 marks · Normal
Answer and see the solution →Two ionic compounds, sodium chloride (NaCl) and magnesium oxide (MgO), have the following melting points:
Compound Melting Point (°C) NaCl 801 MgO 2852 Analyse the data. Explain why magnesium oxide has a much higher melting point than sodium chloride. Your answer should consider the type of particles and the forces between them.
Question 283
2 marks · Normal
Answer and see the solution →State the conditions under which sodium chloride, an ionic compound, is able to conduct electricity.
Question 284
4 marks · Normal
Answer and see the solution →(a)[2 marks]Calcium fluoride is an ionic compound. State whether it will conduct electricity when in solid form and explain your answer.
(b)[2 marks]Describe the arrangement and movement of ions in solid calcium fluoride.
Question 285
3 marks · Normal
Answer and see the solution →A student is asked to test whether lithium bromide conducts electricity in three different states:
- solid lithium bromide
- molten (melted) lithium bromide
- lithium bromide dissolved in water
Explain, using the idea of moving ions, in which of these states lithium bromide will conduct electricity. Show your reasoning for each case.
Question 286
3 marks · Normal
Answer and see the solution →Copper(II) sulfate is an ionic compound. Predict and explain whether it will conduct electricity in each of these conditions: (a) as a solid (b) when dissolved in water. Give reasons for your answers.
Question 287
4 marks · Normal
Answer and see the solution →The table below shows the electrical conductivity of three ionic compounds in solid and molten states.
Substance Conducts when solid? Conducts when molten? Potassium iodide Magnesium oxide Sodium nitrate Complete the table by indicating Yes or No for each box. Then, explain your reasoning for one of your answers.
Question 288
1 mark · Normal
Answer and check →Which of the following best explains why molten potassium bromide conducts electricity?
- A.The ions are free to move and carry charge.
- B.The electrons are free to move between ions.
- C.The molecules are able to gain or lose electrons.
- D.The atoms are bonded together covalently.
Question 289
2 marks · Normal
Answer and see the solution →State two states of ionic substances in which they conduct electricity. For each state, give a reason why conduction is possible.
Question 290
4 marks · Normal
Answer and see the solution →(a)[2 marks]Explain, using particles, why solid magnesium chloride does not conduct electricity.
(b)[2 marks]Describe what changes when magnesium chloride melts and how this allows conduction.