Platinum and vanadium are both transition elements.

1. (a)Transition elements are metals which are hard, strong and have high melting points and boiling points. State two other properties which are typical of transition elements but not of all metals.[2]
2. (b)(i)Vanadium(V) oxide, V₂O₅, is a catalyst in the Contact process. State how a catalyst increases the rate of a chemical reaction.[1]
3. (b)(ii)State the conditions used in the Contact process.[2]
4. (c)Vanadium(V) oxide is reduced to vanadium by heating with aluminium. Complete the equation for this reaction. 3V₂O₅ + .....Al → .....V + .....Al₂O₃[1]
5. (d)(i)A fuel cell generates electricity when hydrogen and oxygen react on platinum electrodes. Name the process used in industry to separate oxygen from air.[1]
6. (d)(ii)The reaction at one of the electrodes in the fuel cell is shown. O₂ + 2H₂O + 4e⁻ → 4OH⁻ State whether this is an oxidation or reduction reaction. Explain your answer.[1]