Vanadium is extracted from vanadium(IV) oxide in a two-stage industrial method.
Stage 1 VO2+2C+2Cl2→VCl4+2CO\quad\text{VO}_2 + 2\text{C} + 2\text{Cl}_2 \rightarrow \text{VCl}_4 + 2\text{CO}VO2+2C+2Cl2→VCl4+2CO
Stage 2 VCl4+2Mg→V+2MgCl2\quad\text{VCl}_4 + 2\text{Mg} \rightarrow \text{V} + 2\text{MgCl}_2VCl4+2Mg→V+2MgCl2
Suggest one hazard associated with Stage 1.
Suggest why the reaction in Stage 2 is carried out in an atmosphere of argon and not in air.
Vanadium(IV) chloride (VCl4\text{VCl}_4VCl4) is a liquid at room temperature. Explain why you would not expect a transition metal chloride to be a liquid at room temperature.
During Stage 2, magnesium atoms are oxidised to magnesium ions. Complete the half-equation for this oxidation.
Mg→Mg2++‾ \text{Mg} \rightarrow \text{Mg}^{2+} + \underline{\qquad\qquad} Mg→Mg2++In Stage 2, 57.9 kg57.9\text{ kg}57.9 kg of vanadium(IV) chloride was added to 15.6 kg15.6\text{ kg}15.6 kg of magnesium. Relative atomic masses (ArA_rAr): Mg=24\text{Mg} = 24Mg=24, Cl=35.5\text{Cl} = 35.5Cl=35.5, V=51\text{V} = 51V=51 Explain why vanadium(IV) chloride is the limiting reactant. You must show your working.
For a Stage 2 reaction, the percentage yield of vanadium was 84.2%84.2\%84.2%. The theoretical maximum mass of vanadium produced in this batch was 21.5 kg21.5\text{ kg}21.5 kg. Calculate the actual mass of vanadium produced. Give your answer to 3 significant figures.
38 exam-style questions on AQA GCSE Chemistry 3.2 Use of amount of substance in relation to masses of pure substances, covering 3.2.1 Moles (HT only), 3.2.2 Amounts of substances in equations (HT only), 3.2.3 Using moles to balance equations (HT only), 3.2.4 Limiting reactants (HT only), and 3.2.5 Concentration of solutions. Each one has a worked solution and a mark scheme showing where the marks go.