Vanadium is a transition metal. It has a melting point of 1910 °C and a density of 6.0 g cm−3\mathrm{g\,cm^{-3}}gcm−3. Vanadium forms ions with different charges: solutions containing V2+\mathrm{V^{2+}}V2+ ions are violet and solutions containing V3+\mathrm{V^{3+}}V3+ ions are green. An oxide of vanadium is used as a catalyst in the manufacture of sulfuric acid.
Give two pieces of information from the passage that show vanadium is a transition metal.
A student heats 5.10 g of vanadium in oxygen until the mass stops changing. The oxide formed has a mass of 9.10 g. Determine the empirical formula of the oxide. Relative atomic masses: V = 51, O = 16.
Explain why the student heats the vanadium until the mass stops changing.
A different oxide of vanadium contains 68.0 % vanadium by mass. Determine the formula of this oxide and deduce the charge on the vanadium ion in it. The oxide ion is O2−\mathrm{O^{2-}}O2−.
The vanadium oxide catalyst is used in the reaction 2SO2(g)+O2(g)⇌2SO3(g)\mathrm{2SO_{2}(g)} + \mathrm{O_{2}(g)} \rightleftharpoons \mathrm{2SO_{3}(g)}2SO2(g)+O2(g)⇌2SO3(g). Explain why using a catalyst reduces the energy costs of the process.
42 exam-style questions on Edexcel GCSE Chemistry 6.1 Transition metals, alloys and corrosion, covering 6.1.1 Properties of transition metals, 6.1.2 Corrosion and its prevention, and 6.1.3 Alloys and the uses of metals. Each one has a worked solution and a mark scheme showing where the marks go.