Metals Banker

1. (a) What is the name of the main ore of aluminium?A bauxiteB cryoliteC hematiteD limestone [1]

1. (a) Name the three solid raw materials added at the top of the blast furnace. [2]
2. (b) Write equations for: (i) carbon burning in hot air to form carbon dioxide; (ii) carbon dioxide reacting with more carbon to form carbon monoxide; (iii) carbon monoxide reducing iron(III) oxide. [3]
3. (c) State why the reaction in (i) is important for the working of the furnace. [1]

Five metals: aluminium, copper, gold, iron, potassium.

1. (a) Which metal is found uncombined (native) in the ground? [1]
2. (b) Which two metals must be extracted by electrolysis of their molten compounds? [2]
3. (c) Which two metals can be extracted by heating their oxides with carbon? [2]
4. (d) State the link between the position of a metal in the reactivity series and its method of extraction. [1]

1. (a) Why is limestone added to the blast furnace?A It reduces iron(III) oxide to iron.B It decomposes to calcium oxide, which reacts with silicon dioxide impurities to form slag.C It burns to provide heat for the furnace.D It lowers the melting point of the iron ore. [1]

1. (a) Explain why aluminium cannot be extracted by heating aluminium oxide with carbon. [1]
2. (b) Explain why the aluminium oxide is dissolved in molten cryolite. [2]
3. (c) Explain why the carbon anodes have to be replaced regularly. [2]
4. (d) Write the ionic half-equation for the reaction at the cathode. [1]

A steel works near Karachi uses an iron ore that contains 80 % iron(III) oxide by mass; the rest is mainly silicon dioxide. [Ar: O = 16, Fe = 56]

1. (a) Calculate the mass of iron(III) oxide in 1000 tonnes of the ore. [1]
2. (b) Calculate the maximum mass of iron that can be produced from 1000 tonnes of the ore.Fe₂O₃ + 3CO → 2Fe + 3CO₂ [2]
3. (c) Write the equation for the formation of slag. [1]

A student reduces 3.20 g of copper(II) oxide by heating it in a horizontal glass tube while a stream of hydrogen passes over it. Excess hydrogen is burned at a small hole at the far end of the tube. [Ar: O = 16, Cu = 64]

1. (a) Describe the colour change seen in the tube. [1]
2. (b) Explain why hydrogen is passed through the tube for a while before heating starts. [1]
3. (c) Explain why hydrogen is kept flowing while the tube cools. [1]
4. (d) Calculate the number of moles of copper(II) oxide used and the mass of copper expected. [2]
5. (e) Write the equation for the reaction and state which substance is reduced. [2]

1. (a) Iron from the blast furnace contains about 4 % carbon. State one property of this iron that makes it unsuitable for most uses. [1]
2. (b) Describe how this iron is converted into steel. Include the role of oxygen and of calcium oxide. [4]

Aluminium is extracted by electrolysis of aluminium oxide dissolved in molten cryolite. [Ar: O = 16, Al = 27]

1. (a) Write the ionic half-equation for the reaction at the anode. [1]
2. (b) Calculate the maximum mass of aluminium that can be obtained from 51 tonnes of aluminium oxide, Al₂O₃. [2]
3. (c) Explain why the process is described as a redox reaction. [2]
4. (d) Suggest why aluminium smelters are often built near hydroelectric power stations. [1]

1. (a) State the oxidation number of iron in Fe₂O₃ and in Fe. [2]
2. (b) State the oxidation number of carbon in CO and in CO₂. [2]
3. (c) Use your answers to identify the oxidising agent and the reducing agent in the reaction Fe₂O₃ + 3CO → 2Fe + 3CO₂. Explain. [2]

[Ar: C = 12, Al = 27]

1. (a) The overall reaction in the cell is 2Al₂O₃ → 4Al + 3O₂. Calculate the number of moles of oxygen formed when 108 kg of aluminium is produced. [2]
2. (b) Assume all the oxygen reacts with the carbon anode to form carbon dioxide: C + O₂ → CO₂. Calculate the mass of carbon used, in kg. [2]
3. (c) Name one environmental problem caused by this anode reaction. [1]

A student heated a mixture of each metal oxide with powdered carbon in a crucible for ten minutes.Copper(II) oxide: pink-brown solid formedLead(II) oxide: silvery beads of metal formedMagnesium oxide: no changeAluminium oxide: no change[Ar: O = 16, Pb = 207]

1. (a) Use the results to place carbon in the reactivity series relative to copper, lead, magnesium and aluminium. [2]
2. (b) Calculate the mass of lead that could be obtained from 2.23 g of lead(II) oxide, PbO. [2]
3. (c) Write the equation for the reaction of lead(II) oxide with carbon, forming carbon dioxide. [1]
4. (d) Suggest why aluminium oxide gave no reaction with carbon. [1]

1. (a) A metal reacts vigorously with cold water, floats and moves about on the surface, and gives off hydrogen. Which metal could it be?A copperB ironC sodiumD zinc [1]

Observations:Calcium: fizzes steadily in cold water.Magnesium: very slow reaction with cold water; burns brightly when heated in steam.Iron: no reaction with cold water; reacts slowly when heated strongly in steam.Copper: no reaction with water or steam.

1. (a) Put the four metals in order of reactivity, most reactive first. [2]
2. (b) Name the gas formed when calcium reacts with water and describe a test for it. [2]
3. (c) Write the word equation for magnesium reacting with steam. [1]

1. (a) Which mixture would react?A copper + magnesium sulfate solutionB zinc + copper(II) sulfate solutionC silver + iron(II) sulfate solutionD iron + zinc sulfate solution [1]

Each metal was added to solutions of the nitrates of the other metals. ✓ = reaction, ✗ = no reaction.Metal W: with X nitrate ✓, with Y nitrate ✗, with Z nitrate ✓Metal X: with W nitrate ✗, with Y nitrate ✗, with Z nitrate ✗Metal Y: with W nitrate ✓, with X nitrate ✓, with Z nitrate ✓Metal Z: with W nitrate ✗, with X nitrate ✓, with Y nitrate ✗

1. (a) Use the results to put metals W, X, Y and Z in order of reactivity, most reactive first. [2]
2. (b) Metal Y is magnesium and metal X is copper. Write the ionic equation for the reaction of magnesium with copper(II) ions. [2]
3. (c) In the reaction in (b), state which species is oxidised. Explain in terms of electrons. [2]

Equal masses of four metal powders were added separately to 50 cm³ of 1.0 mol/dm³ hydrochloric acid. The volume of hydrogen collected in a gas syringe in the first 60 seconds was recorded.Magnesium: 48 cm³Zinc: 21 cm³Iron: 6 cm³Copper: 0 cm³

1. (a) Calculate the average rate of gas production, in cm³/s, for magnesium, zinc and iron. [2]
2. (b) State the order of reactivity shown by the results. [1]
3. (c) Explain why copper gave no gas. [1]
4. (d) State two variables that must be controlled. [2]

1. (a) Explain the order of reactivity of metals in terms of their ions. [1]
2. (b) Aluminium is high in the reactivity series, yet aluminium cooking pots do not react with water. Explain why. [2]
3. (c) An iron nail is placed in aqueous copper(II) sulfate. Describe two observations and write the ionic equation. [3]

A metal M forms M²⁺ ions. M displaces iron from aqueous iron(II) sulfate but does not react with aqueous zinc sulfate.

1. (a) Write the ionic equation for the reaction of M with iron(II) ions. [2]
2. (b) Place M in the reactivity series relative to zinc, iron and copper. [1]
3. (c) Predict whether M would react when heated with copper(II) oxide. Explain. [2]
4. (d) Predict whether the oxide of M could be reduced by heating it with carbon. Explain. [1]

1. (a) Overhead power cables are made of aluminium wrapped round a steel core. Which properties make aluminium suitable?A high density and good electrical conductivityB low density and good electrical conductivityC low density and poor electrical conductivityD high melting point and magnetic [1]

1. (a) State three physical properties of metals. [3]
2. (b) Metals react with oxygen to form oxides. State the type of oxide formed by most metals and how it reacts with acids. [2]
3. (c) State one physical property in which non-metals generally differ from metals. [1]

1. (a) Copper is used for electrical wiring in houses. Give two properties of copper that make it suitable. [2]
2. (b) Aluminium is used to make aircraft bodies. Give two reasons. [2]
3. (c) Aluminium is also used for food containers and foil. Explain why it does not corrode easily. [1]

Data for four metals:Metal P: density 2.7 g/cm³, relative electrical conductivity 61, melting point 660 °C, resists corrosion, low costMetal Q: density 8.9 g/cm³, relative electrical conductivity 100, melting point 1085 °C, resists corrosion, medium costMetal R: density 7.9 g/cm³, relative electrical conductivity 17, melting point 1538 °C, rusts, very low costMetal S: density 4.5 g/cm³, relative electrical conductivity 4, melting point 1668 °C, resists corrosion, high cost

1. (a) Calculate the mass of a 500 cm³ bracket made of each metal. [2]
2. (b) Which metal would be best for electrical cables carried on pylons? Explain using the data. [2]
3. (c) Which metal would be best for a part of a jet engine that becomes very hot and must stay strong? Explain. [2]
4. (d) Suggest why Q is used for house wiring even though it is more dense than P. [1]

1. (a) Define an alloy. [1]
2. (b) Explain why an alloy is usually harder and stronger than the pure metal it is made from. [3]
3. (c) Give one use of brass and the property it depends on. [1]

1. (a) Which metals are mixed to make brass?A copper and tinB copper and zincC iron and carbonD iron and chromium [1]

The city of Sialkot exports surgical instruments made of stainless steel.

1. (a) Name the main metal in stainless steel and two other elements added to it. [2]
2. (b) Calculate the mass of chromium and the mass of nickel in a 250 g instrument made of 18/8 stainless steel (18 % chromium and 8 % nickel by mass). [2]
3. (c) Explain why stainless steel, rather than mild steel, is chosen for surgical instruments. [2]
4. (d) Give one use of mild steel. [1]

1. (a) Which substances must both be present for iron to rust?A oxygen and waterB carbon dioxide and waterC nitrogen and oxygenD oxygen and salt [1]

Four identical iron nails were set up for one week:Tube A: nail in tap water, open to air. Mass increase 0.12 g.Tube B: nail in boiled water with a layer of oil on top. Mass increase 0.00 g.Tube C: nail in air with anhydrous calcium chloride, stoppered. Mass increase 0.00 g.Tube D: nail in salt water, open to air. Mass increase 0.21 g.

1. (a) In which tubes did the nails rust? [1]
2. (b) Explain why the nail in tube B did not rust. [2]
3. (c) Explain why the nail in tube C did not rust. [1]
4. (d) Calculate how many times greater the mass increase was in tube D than in tube A. Give your answer to 2 significant figures. [1]
5. (e) Suggest why car bodies rust faster in coastal cities such as Karachi. [1]

1. (a) Explain how painting a steel gate prevents rusting. [1]
2. (b) Name the metal used to galvanise steel roof sheets. [1]
3. (c) A galvanised roof sheet is scratched, exposing the steel. Explain why the steel still does not rust. [2]
4. (d) Explain why a scratched painted gate does rust. [1]

Blocks of zinc are bolted to the steel hulls of ships in Karachi port, below the waterline.

1. (a) Name the type of protection given by the blocks. [1]
2. (b) Write the half-equation for the reaction of the zinc blocks and explain why it protects the steel. [2]
3. (c) An engineer suggests using copper blocks instead. Explain why this would not work. [2]
4. (d) State the chemical name of rust. [1]
5. (e) Explain why the zinc blocks must be replaced from time to time. [1]