WJEC Chemistry for AS: Student Bk

1.1 1 Given that the formula for the phosphate ion is PO 4 3− , write the formula of calcium phosphate. [1] 2 A metal M forms a sulfate with the formula MSO 4 . Write the formula of its hydroxide. [1] 3 State the oxidation number of chromium in CrO 2 Cl 2 . [1] 4 Magnetite ore can be reduced by carbon monoxide in a blast furnace to produce iron as part of steel production. Balance the equation for the reduction of magnetite. [1] Fe 3 O 4 + CO → Fe + CO 2 5 When ethanol, C 2 H 5 OH, is burned in an excess of air, the only products are carbon dioxide and water. Balance the equation for this reaction. [1] C 2 H 5 OH + O 2 → CO 2 + H 2 O 6 When calcium is added to cold water, calcium hydroxide and hydrogen form. Write the balanced chemical equation for this reaction. [1] 7 Write a balanced equation for the reaction between PCl 5 and water to form H 3 PO 4 and HCl only. [1] 8 Write an ionic equation, including state symbols, for the reaction between hydrochloric acid and magnesium to form aqueous magnesium chloride and hydrogen. [1] 9 Methane reacts with hot copper(I) oxide to produce copper, carbon dioxide and steam. Write the balanced chemical equation for this reaction. [1] 10 Magnesium nitride, Mg 3 N 2 , reacts with water to form magnesium hydroxide and ammonia. Write the balanced chemical equation for this reaction. [1] 11. One of the main uses of ammonia is in the production of nitric acid. In the first part of this process a mixture of ammonia and air is passed over a catalyst at 850ºC. NH 3 (g) + O 2 (g) → NO(g) + H 2 O(g) (a) Balance the equation above. [1] (b) Complete the table below to give the oxidation numbers (states) of each element present. [3] Element Initial oxidation number Final oxidation number Nitrogen Hydrogen Oxygen Unit 1 Exam practice questions 76