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
721–730 of 991
Question 721
1 mark · Normal
Answer and check →Which statement describes the effect of increasing molecular mass on the boiling point of simple molecular substances?
- A.Boiling point decreases as molecular mass increases.
- B.Boiling point stays the same as molecular mass increases.
- C.Boiling point increases as molecular mass increases.
- D.Boiling point alternates up and down as molecular mass increases.
Question 722
2 marks · Normal
Answer and see the solution →Explain why substances with simple molecular structures do not conduct electricity, even when melted.
Question 723
4 marks · Normal
Answer and see the solution →A student compares the properties of diamond (a giant covalent structure) with carbon dioxide (a simple molecular compound).
(a)[1 mark]State one difference between the melting points of diamond and carbon dioxide.
(b)[2 marks]Explain this difference in terms of bonding and structure.
(c)[1 mark]Which of the two substances can conduct electricity? Explain your answer.
Question 724
2 marks · Hard
Answer and see the solution →Explain, using ideas about bonds and forces, why melting a substance with a simple molecular structure requires much less energy than melting a giant covalent structure such as diamond.
Question 725
5 marks · Hard
Answer and see the solution →The table shows data for three simple molecular substances:
Substance Relative molecular mass (Mr) Melting point (°C) Boiling point (°C) Electrical conductivity A 32 -210 -183 does not conduct B 44 -56 -1 does not conduct C 160 -7 59 does not conduct (a)[2 marks]Describe the trend shown by the melting points and boiling points as the relative molecular mass increases.
(b)[2 marks]Substance C is liquid at room temperature (25°C). Explain why substance C is a liquid at this temperature but substance A is a gas.
(c)[1 mark]Explain why none of these substances conduct electricity in any state.
Question 726
2 marks · Hard
Answer and see the solution →State one property that distinguishes a simple molecular structure from a giant covalent structure. Explain how this property relates to the forces present in each structure.
Question 727
1 mark · Easy
Answer and see the solution →State which form of carbon, out of diamond, graphite, and C60 fullerene, conducts electricity the best.
Question 728
3 marks · Easy
Answer and see the solution →(a)[1 mark]Describe the structure of diamond in terms of the arrangement of its carbon atoms.
(b)[1 mark]Describe the structure of graphite in terms of the arrangement of its carbon atoms.
(c)[1 mark]State the type of structure present in C60 fullerene.
Question 729
2 marks · Easy
Answer and see the solution →Diamond has a melting point of about 3550 °C, while C60 fullerene melts at about 280 °C. Use these values to explain, in terms of bonding, why diamond has such a high melting point compared to C60 fullerene.
Question 730
2 marks · Easy
Answer and see the solution →Explain why C60 fullerene does not conduct electricity as well as graphite, referring to their structures.