AQA A LEVEL CHEMISTRY- INORGANIC CHEMISTRY QUESTIONS AND ANSWERS WITH SOLUTIONS 2024

AQA A LEVEL CHEMISTRY - INORGANIC CHEMISTRY QUESTIONS AND ANSWERS WITH SOLUTIONS 2024 Periodic table - ANSWER Table that provides chemists with a structural organisation of the known chemical elements that can be used to deduce physical and chemical properties Atomic radius across Period 3 - ANSWER Decreases First ionisation energy across Period 3 - ANSWER Increases Exceptions: Drops at Al and S Melting points across Period 3 - ANSWER Increases from Na to Si Decreases from Si to Ar Small rise at S Explain why the melting point of aluminium is higher than the melting point of sodium - ANSWER Bigger charge (3+ compared to 1+) More free/delocalised electrons Stronger metallic bonding/stronger (electrostatic) attraction between the ions electrons Explain why the melting point of sulfur is higher than the melting point of phosphorus - ANSWER S bigger molecule So more/stronger van der Waals' forces (to be broken or overcome) Atomic radius down Group 2 - ANSWER Increases First ionisation energy down Group 2 - ANSWER Decreases Melting point down Group 2 - ANSWER Decreases Exception Ca which increases Explain the melting point of the elements in terms of the structure and bonding of Group 2 elements - ANSWER Be and Mg have hexagonal close packed structures Ca, Sr and Ba have cubic structures The relative solubilities of the hydroxides, X(OH)2, of the elements Mg -Ba in water - ANSWER Increase down the group The relative solubilities of the sulfates, XSO4, of the elements Mg -Ba in water - ANSWER Decrease down the group The role of magnesium in the extraction of titanium from TiCl4 - ANSWER Mg is used as a reducing agent Mg is oxidised to 2+ in MgO when it is heated with TiCl4 to about 1200C in an inert atmosphere Redox equation of Group 2 elements with water - ANSWER X(s) + 2H2O(l) -> X2+(aq) +2OH -(aq) + H2(g) Sparingly soluble Group 2 hydroxide - ANSWER Mg(OH)2 Insoluble Group 2 sulphate - ANSWER BaSO4 The use of acidified BaCl2 solution - ANSWER Test for sulfate ions If Barium Chloride is added to a solution that contains sulphate ions a white precipitate forms (BaSO4) The use of Mg(OH)2 in medicine - ANSWER (in solution as milk of magnesia) to neutralise excess acid in the stomach and to treat constipation The use of BaSO4 in medicine - ANSWER In a 'Barium meal' given to patients who need x -rays of their intestines. The Barium absorbs the x -rays and so the gut shows up on the x -ray image. Even though Barium compounds are toxic it is safe to use here because of its low solubility