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
271–280 of 423 · Normal
Question 271
1 mark · Normal
Answer and check →Which property best explains why potassium chloride has a high melting point?
- A.It consists of molecules joined by covalent bonds.
- B.Its ions are arranged in layers that slide past each other.
- C.It is made of positive and negative ions held by strong electrostatic forces.
- D.It has delocalised electrons that conduct electricity.
Question 272
2 marks · Normal
Answer and see the solution →Describe the structure of a giant ionic compound and explain how this structure is linked to its melting point.
Question 273
4 marks · Normal
Answer and see the solution →Calcium chloride is an ionic compound with the formula CaCl_2.
(a)[1 mark]Name the ions present in calcium chloride.
(b)[2 marks]Explain why calcium chloride is soluble in water but does not conduct electricity when solid.
(c)[1 mark]What must happen for solid calcium chloride to conduct electricity?
Question 274
3 marks · Normal
Answer and see the solution →A student is comparing the melting points and electrical conductivity of two compounds: sodium chloride (NaCl) and magnesium oxide (MgO).
(a)[1 mark]Sodium chloride melts at around 801°C, while magnesium oxide melts at about 2852°C. Calculate the difference in melting points between these two ionic compounds.
(b)[2 marks]Explain, using the structure and bonding in giant ionic lattice structures, why magnesium oxide has a much higher melting point than sodium chloride.
Question 275
2 marks · Normal
Answer and see the solution →Describe the arrangement of ions in the giant ionic lattice of sodium chloride.
Question 276
4 marks · Normal
Answer and see the solution →(a)[1 mark]State what holds the ions together in the lattice of an ionic compound such as sodium chloride.
(b)[2 marks]Explain, with reference to the lattice structure, why sodium chloride has a high melting point.
(c)[1 mark]Sodium chloride and magnesium oxide have similar lattice structures. Explain why magnesium oxide has a higher melting point.
Question 277
3 marks · Normal
Answer and see the solution →Explain why sodium chloride forms a giant ionic lattice instead of individual molecules. In your answer, refer to the charges on the ions and the overall structure.
Question 278
1 mark · Normal
Answer and check →Which statement best explains why ionic compounds, such as sodium chloride, are often crystalline?
- A.Because their ions are free to move in the lattice.
- B.Because the ions are arranged in a regular repeating pattern.
- C.Because they are made up of molecules.
- D.Because they contain only one type of atom.
Question 279
2 marks · Normal
Answer and see the solution →State what is meant by a 'giant ionic lattice' as found in sodium chloride.
Question 280
4 marks · Normal
Answer and see the solution →(a)[2 marks]Explain why a large amount of energy is required to melt an ionic compound such as sodium chloride.
(b)[2 marks]Compare the melting points of sodium chloride and potassium chloride. Both are ionic, but sodium chloride melts at 801 °C and potassium chloride at 770 °C. Suggest a reason for this difference.