9.4. Reactivity series
A subsection of Chemistry, 0620, through 9. Metals
Listing 10 of 452 questions
Concentrated hydrochloricacid is electrolysed using graphite electrodes. Name the products of this electrolysis at: the positive electrode the negative electrode.  Suggest one observation that is made at the negative electrode. Dilute hydrochloricacid reacts with zinc. Complete the word equation for this reaction. zinc + hydrochloric acid +  The following statements are about the procedure for making crystals of hydrated zincsulfate from zinc and dilute sulfuricacid. A Warm the mixture until no more bubbles are seen. B Add excess zinc to dilute sulfuric acid. C Warm the filtrate to the point of crystallisation. D Leave the mixture at room temperature to form more crystals. E Filter off the excess zinc. F Filter off the crystals and dry between filter papers. Put the statements A, B, C, D, E and F in the correct order. The first one has been done for you. B  Zinc is a metal. Describe three physical properties which are characteristic of metals.  An alloy of zinc, copper and nickel is used to make coins. Suggest two reasons why an alloy is used to make coins and not pure copper alone.  
0620_w19_qp_32
THEORY
2019
Paper 3, Variant 2
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Name the ore of aluminium which mainly consists of aluminium oxide. Aluminium is produced by the electrolysis of aluminium oxide dissolved in molten cryolite. negative electrode positive electrode molten mixture of aluminium oxide and cryolite aluminium waste gases Give two reasons why the electrolysis is done using a molten mixture of aluminiumoxide and cryolite instead of molten aluminiumoxide only.  Write ionic half-equations for the reactions occurring at the electrodes. positive electrode negative electrode  The anodes are made of carbon and have to be replaced regularly. Explain why the carbon anodes have to be replaced regularly. The positions of some common metals in the reactivity series are shown. most reactive magnesium aluminium least reactive copper When magnesium is placed in aqueous copper(sulfate a displacement reaction occurs immediately. Write an ionic equation for the reaction. Include state symbols. State two observations you would make when magnesium is placed in aqueous copper(sulfate.  When aluminium foil is added to aqueous copper(sulfate no immediate reaction takes place. Explain why. Aluminium powder reacts with iron(oxide to produce aluminiumoxide and iron. Write a chemical equation for this reaction. 
0620_w19_qp_43
THEORY
2019
Paper 4, Variant 3
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The structure of tartaric acid is shown. C C H O O H O H H O C C H O O H On the structure, draw a circle around one alcohol functional group. Deduce the formula of tartaricacid to show the number of carbon, hydrogen and oxygen atoms. Complete the table to calculate the relative molecular mass of tartaricacid. Use your Periodic Table to help you. type of atom number of atoms relative atomic mass carbon hydrogen 6 × 1 = 6 oxygen  relative molecular mass = Acids react with bases such as calciumhydroxide. Complete the word equation for the reaction of nitricacid with calciumhydroxide. nitric acid + calcium hydroxide +  An aqueous solution of calciumhydroxide is alkaline. Identify which one of these pH values represents the pH of an alkaline solution. Draw a circle around the correct answer. pH 1 pH 4 pH 7 pH 10 One way of determining pH is to use a pH meter. Describe one other way of determining pH. Farmers spread calciumhydroxide (slaked lime) on fields where crops are grown. Explain why. Calciumcarbonate undergoes thermal decomposition. CaCO3 → CaO + CO2 State the meaning of the term thermal decomposition. Complete the energy level diagram for the thermal decomposition of calciumcarbonate by writing these words on the diagram: ● ● reactant ● ● products. energy progress of reaction  Explain, using information on the energy level diagram, how you know that this reaction is endothermic. 
0620_w20_qp_31
THEORY
2020
Paper 3, Variant 1
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This question is about metals and compounds of metals. Iron reacts with dilute hydrochloricacid to form an iron(salt and a gas which pops with a lighted splint. Complete the word equation for this reaction. iron + hydrochloric acid +  Identify two correct statements about iron. Tick two boxes. Iron forms an alloy called steel. The commonest ore of iron is called bauxite. Iron is usually extracted from its ore by electrolysis. Iron is oxidised by carbon in the blast furnace. Both oxygen and water are needed for iron to rust.  The table compares the reactions of four metals with warm water and with steam. metal reaction with warm water reaction with steam chromium no reaction slow reaction copper no reaction no reaction iron very slow reaction slow reaction magnesium very slow reaction rapid reaction Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive  Crystals of cobalt(chloride, CoCl 2•6H2O, can be prepared by reacting excess cobalt(carbonate powder with dilute hydrochloricacid. Describe how to prepare a sample of pure dry cobalt(chloride crystals after the reaction is complete. In your answer describe how to: ● ● remove the excess cobalt(carbonate from the reaction mixture ● ● crystallise the cobalt(chloride ● ● dry the crystals. A few drops of water were added to a sample of solid anhydrous cobalt(chloride, CoCl 2. The equation for the reaction is shown. CoCl 2 + 6H2O CoCl 2•6H2O State the meaning of the symbol . State the colour change observed when water is added to anhydrous cobalt(chloride. from to 
0620_w20_qp_32
THEORY
2020
Paper 3, Variant 2
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This question is about metals and compounds of metals. Sodium is a metal in GroupI of the Periodic Table. Identify two correct statements about sodium. Tick two boxes. It is a relatively soft metal. It has a high melting point. It forms coloured chlorides. It has a lower density than most metals. It is a good insulator.  Some changes of state of sodium are shown. solid sodium melting R liquid sodium sodium gas S condensing Give the names of the changes of state represented by R and S. R S  The table compares the reactions of four metals with dilute and with concentrated hydrochloricacid. metal observation with dilute hydrochloric acid observation with concentrated hydrochloric acid beryllium bubbles form rapidly bubbles form very rapidly copper no bubbles seen no bubbles seen iron bubbles form very slowly bubbles form slowly nickel no bubbles seen bubbles form slowly Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive  Crystals of magnesium chloride, MgCl 2•6H2O, can be prepared by adding excess magnesium powder to dilute hydrochloricacid. Describe how to prepare a sample of pure dry magnesiumchloride crystals after the reaction is complete. In your answer describe how to: ● ● remove the excess magnesium from the reaction mixture ● ● crystallise the magnesiumchloride ● ● dry the crystals. When magnesium reacts with concentrated sulfuricacid, sulfurdioxide is produced. Complete this description of the test for sulfurdioxide using words from the list. blue chloride colourless green manganate(sulfate(The test for sulfurdioxide uses acidified aqueous potassium . The colour change is from purple to .  Green nickel(sulfate crystals turn yellow when heated. NiSO4•7H2O NiSO4 + 7H2O green yellow nickel(sulfate nickel(sulfate Suggest how you would change yellow nickel(sulfate to green nickel(sulfate. Identify which word best describes green nickel(sulfate with the formula NiSO4•7H2O. Draw a circle around the correct answer. anhydrous decomposed hydrated oxidised reduced 
0620_w20_qp_33
THEORY
2020
Paper 3, Variant 3
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Zinc is manufactured from zincblende. Zincblende is an ore which consists mainly of zincsulfide, ZnS. Zincblende is roasted in air. One of the products is zincoxide. Name the other product formed in this reaction. Zincoxide is then converted into zinc. Zincoxide and coke, a source of carbon, are heated in a furnace. Hot air is blown into the furnace. Give two reasons why coke is needed.  Write a chemical equation for the formation of zinc in the furnace. Zinc has a melting point of 420 °C and a boiling point of 907 °C. The temperature inside the furnace is 1200 °C. Explain how this information shows that the zinc produced inside the furnace is a gas. The gaseous zinc is converted to molten zinc. Name this change of state. Zinc reacts with dilute sulfuricacid to produce aqueous zincsulfate. Zn+ H2SO4→ ZnSO4+ H2Hydrated zincsulfate crystals are made from aqueous zincsulfate. Step 1 Solid zinc is added to dilute sulfuricacid until zinc is in excess. Step 2 Excess zinc is separated from aqueous zincsulfate by filtration. Step 3 Aqueous zincsulfate is heated until the solution is saturated. Step 4 The saturated solution is allowed to cool and crystallise. Step 5 The crystals are removed and dried. Name the residue in step2. In step3, a saturated solution is produced. Describe what a saturated solution is. Name two compounds each of which react with dilute sulfuricacid to produce aqueous zincsulfate.  When hydrated magnesiumsulfate crystals, MgSO4•xH2O, are heated they give off water. MgSO4•xH2O→ MgSO4+ xH2OA student carries out an experiment to determine the value of x in MgSO4•xH2O. Step 1 Hydrated magnesiumsulfate crystals were weighed. Step 2 Hydrated magnesiumsulfate crystals were heated. Step 3 The remaining solid was weighed. Describe how the student can ensure that all the water is given off. In an experiment, all the water was removed from 1.23 g of MgSO4•xH2O. The mass of MgSO4 remaining was 0.60 g. Mr: MgSO4 = 120; Mr: H2O = 18 Determine the value of x using the following steps. ● Calculate the number of moles of MgSO4 remaining.  moles of MgSO4 = ● Calculate the mass of H2O given off.  mass of H2O = g ● Calculate the moles of H2O given off.  moles of H2O = ● Determine the value of x.  x =  
0620_w20_qp_43
THEORY
2020
Paper 4, Variant 3
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