9. Metals
A section of Chemistry, 0620
Listing 10 of 1272 questions
Iron is extracted from its ore by heating the ore with carbon in a blast furnace. State the name of an ore of iron. In the blast furnace, iron(oxide is reduced by carbon monoxide. Explain how the carbon monoxide is formed in the blast furnace. Balance the chemical equation for this reaction. Fe2O3 + 3CO Fe + CO2 How does this equation show that iron(oxide is reduced? Calculate the relative formula mass of iron(oxide, Fe2O3. Show all your working. Use your Periodic Table to help you. relative formula mass = Iron reacts with hydrochloric acid to form iron(chloride and a gas which ‘pops’ with a lighted splint. Identify this gas. Suggest a practical method for investigating the rate of this reaction involving collection of the gas. You may include a labelled diagram in your answer. Describe a test for iron(ions. test result Give two advantages of recycling steel.
0620_s17_qp_33
THEORY
2017
Paper 3, Variant 3
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Magnesium sulfate and lead(sulfate are examples of salts. A student prepared magnesium sulfate crystals starting from magnesium carbonate. The student carried out the experiment in four steps. step 1 The student added excess magnesium carbonate to a small volume of dilute sulfuric acid until no more magnesium carbonate would react. step 2 The student filtered the mixture. step 3 The student heated the filtrate obtained from step 2 until it was saturated. step 4 The student allowed the hot filtrate to cool to room temperature and then removed the crystals which formed. How did the student know when the reaction had finished in step 1? Name the residue in step 2. A saturated solution forms in step 3. What is a saturated solution? Explain why magnesium sulfate crystals form during step 4. Magnesium sulfate crystals are hydrated. Another student heated some hydrated magnesiumsulfate crystals in a crucible and obtained the following results. mass of hydrated magnesium sulfate crystals = 4.92 g mass of water removed = 2.52 g Calculate the number of moles of water removed. moles of water = mol Calculate the number of moles of anhydrous magnesium sulfate remaining in the crucible. The Mr of anhydrous magnesium sulfate is 120. moles of anhydrous magnesium sulfate = mol Calculate the ratio of moles of anhydrous magnesium sulfate : moles of water. Give your answer as whole numbers. ratio = : Suggest the formula of hydrated magnesium sulfate crystals. formula of hydrated magnesium sulfate crystals = Lead(sulfate, PbSO4, is insoluble. Describe how you would prepare a pure dry sample of lead(sulfate crystals starting from solutions of lead(nitrate and sodium sulfate. Include a series of key steps in your answer. Write the ionic equation for the reaction which takes place between solutions of lead(nitrate and sodium sulfate. Include state symbols.
0620_s17_qp_41
THEORY
2017
Paper 4, Variant 1
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Zinc is a very important metal. Zinc is extracted from its ore, zinc blende. Zinc blende contains zinc sulfide, ZnS. Zinc sulfide is converted to zinc oxide in an industrial process. Describe how zinc sulfide is converted to zinc oxide in this industrial process. Write the chemical equation for this reaction. Zinc oxide is then reduced in a furnace. Name the substance added to the furnace to reduce the zinc oxide. Describe how the pure zinc is removed from the furnace and collected. When rods of zinc and copper are placed into dilute sulfuric acid as shown, electricity is generated. copper rod dilute sulfuric acid zinc rod bulb Write the ionic half-equation for the reaction occurring at the zinc rod. Write the ionic half-equation for the reaction occurring at the copper rod. The copper rod was replaced by an iron rod. Suggest the change, if any, in the intensity of the light emitted from the bulb and give a reason for your answer. change reason
0620_s17_qp_41
THEORY
2017
Paper 4, Variant 1
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Nickel, copper and zinc are three consecutive elements in the Periodic Table. Nickel and copper are transition elements. State three chemical properties of transition elements. Copper(oxide is a basic oxide but zinc oxide is an amphoteric oxide. Both oxides are insoluble in water. You are provided with a mixture of solid copper(oxide and solid zinc oxide. Describe how you would obtain a sample of copper(oxide from this mixture. Three cells are set up each using two metals. cell 1 1.10 V electrolyte zinc copper – + – + V cell 2 0.51 V electrolyte zinc nickel V cell 3 V electrolyte copper nickel V Write the ionic half-equation for the reaction occurring at the zinc electrode in cell 1. Put the three metals, copper, nickel and zinc, in order of reactivity. most reactive least reactive Complete the labelling in cell 3 by writing the polarity (+/–) of each electrode in the circles and calculating the reading on the voltmeter.
0620_s17_qp_42
THEORY
2017
Paper 4, Variant 2
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Questions Discovered
1272