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
711–720 of 991
Question 711
2 marks · Easy
Answer and see the solution →Explain why methane (CH₄) has a much lower boiling point than water (H₂O), using ideas about molecular mass and intermolecular forces.
Question 712
3 marks · Easy
Answer and see the solution →Examine the table below showing properties of some substances.
Properties of Substances Substance Structure Melting point (°C) Boiling point (°C) Oxygen simple molecular -219 -183 Graphite giant covalent 3930 4830 Sulphur dioxide simple molecular -73 -10 (a)[1 mark]Which substance in the table is likely to have the hardest structure? Give a reason.
(b)[2 marks]Explain why oxygen has a much lower melting point than graphite.
Question 713
1 mark · Easy
Answer and see the solution →State what happens to the boiling point of chlorine (Cl₂) as its relative molecular mass increases.
Question 714
3 marks · Easy
Answer and see the solution →Describe the structure and properties of a substance with a simple molecular structure.
(a)[1 mark]State the type of bonds within a simple molecule.
(b)[1 mark]Describe the forces between the molecules.
(c)[1 mark]Explain why these substances have low melting and boiling points.
Question 715
2 marks · Easy
Answer and see the solution →The melting point of fluorine is –220°C and its boiling point is –188°C. Calculate how many degrees fluorine is a liquid.
Question 716
2 marks · Normal
Answer and see the solution →State two characteristic physical properties of substances with simple molecular structures and explain why they have these properties.
Question 717
4 marks · Normal
Answer and see the solution →The table shows the relative molecular mass and boiling points for two gaseous substances:
Gases and their boiling points Substance Relative molecular mass (Mr) Boiling point (°C) Methane 16 –161 Sulfur hexafluoride 146 –64 (a)[2 marks]Explain why both methane and sulfur hexafluoride are gases at room temperature despite having different molecular masses.
(b)[2 marks]Explain how increasing the molecular mass affects the boiling point of simple molecular substances, using these examples.
Question 718
3 marks · Normal
Answer and see the solution →Hexane is a simple molecular compound. It melts at –95°C and boils at 69°C. Calculate the temperature range (in °C) over which hexane is a liquid and explain why this range exists for simple molecular substances.
Question 719
3 marks · Normal
Answer and see the solution →Explain why bromine (Br2) is a liquid at room temperature, whereas chlorine (Cl2) is a gas, in terms of molecular mass and intermolecular forces.
Question 720
4 marks · Normal
Answer and see the solution →Analyze the data in the table below and answer the questions.
Melting and boiling points of halogens Halogen Formula Relative molecular mass (Mr) Melting point (°C) Boiling point (°C) Fluorine F2 38 –220 –188 Chlorine Cl2 71 –101 –34 Bromine Br2 160 –7 59 Iodine I2 254 114 184 (a)[1 mark]Describe the trend in boiling points as you go down the group from fluorine to iodine.
(b)[2 marks]Explain this trend in terms of molecular structure and forces.
(c)[1 mark]Which halogen is a solid at room temperature (25°C)? Explain how you decided.