GCSE COMBINED SCIENCE: TRILOGY Higher Tier Chemistry Paper 1H

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This question is about the extraction of aluminium. An aluminium atom is represented as: Al1327 Give the number of electrons and neutrons in the aluminium atom. [2 marks] Number of electrons ... Number of neutrons Aluminium is extracted by the electrolysis of a molten mixture of aluminium oxide and cryolite. Figure 1 shows the cell used for the electrolysis. Figure 1 Aluminium is produced by the reduction of aluminium oxide (Al2O3). What is meant by the term reduction? [1 mark] Do not write outside the box IB/M/Jun20/8464/C/1H Do not write outside the box Oxygen is formed at the positive carbon electrodes. Explain why the positive carbon electrodes must be continually replaced. [3 marks] A substance conducts electricity because of free moving, charged particles. What are the free moving, charged particles in a: • carbon electrode (made from graphite) • molten mixture of aluminium oxide and cryolite • metal wire? [3 marks] Carbon electrode (made from graphite) Molten mixture of aluminium oxide and cryolite Metal wire Turn over for the next question IB/M/Jun20/8464/C/1H Do not write outside the box This question is about substances with covalent bonding. Figure 2 shows a ball and stick model of a water molecule (H2O). Figure 2 Suggest one limitation of using a ball and stick model for a water molecule. [1 mark] Ice has a low melting point. Water molecules in ice are held together by intermolecular forces. Complete the sentence. [1 mark] Ice has a low melting point because the intermolecular forces are IB/M/Jun20/8464/C/1H Do not write outside the box Figure 3 shows the structure of a molecule. Figure 3 What is the molecular formula of the molecule in Figure 3? [1 mark] Question 2 continues on the next page 6 *06* IB/M/Jun20/8464/C/1H Do not write outside the box 8 Diamond has a giant covalent structure. What is the number of bonds formed by each carbon atom in diamond? [1 mark] Tick () one box. Give two physical properties of diamond. [Show More]

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