5070_w24_qp_21
A paper of Chemistry, 5070
Questions:
7
Year:
2024
Paper:
2
Variant:
1
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1
shows the electronic configurations of five atoms, D, E, F, G and H. D E F G H Answer the questions about these electronic configurations. Each electronic configuration may be used once, more than once or not at all. State which electronic configuration, D, E, F, G or H, represents: an atom of an element in Group VI of the Periodic Table an atom that forms an ion that gives a lilac colour in a flame test an atom of a monatomic gas an atom of an element that is used in the treatment of the domestic water supply to remove tastes and odours an atom that forms a stable ion by losing two electrons. Deduce the number of protons and neutrons in the chromium atom shown. 24Cr number of protons number of neutrons
2. Atoms, elements and compounds  →  2.2. Atomic structure and the Periodic Table
8. The Periodic Table  →  8.1. Arrangement of elements
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2
Iron is extracted in a blast furnace by the reduction of iron(oxide with carbon monoxide. Fe2O3 + 3CO 2Fe + 3CO2 This reaction is a redox reaction. State the meaning of the term redox reaction. Explain how carbon monoxide acts as a reducing agent in this reaction. Calcium carbonate is added to the blast furnace. The calcium carbonate undergoes thermal decomposition. CaCO3 CaO + CO2 The thermal decomposition of calcium carbonate is endothermic. Complete the reaction pathway diagram in to show: • the reactant and products • a labelled arrow for the activation energy, Ea • a labelled arrow for the enthalpy change, ΔH. energy progress of reaction Describe how slag is formed in the blast furnace. Include a symbol equation in your answer. Iron is a transition element. Transition elements have coloured compounds. State two other physical properties that are typical of transition elements and not of Group I metals. The equation shows the decomposition of iron pentacarbonyl, Fe(CO)5, in a closed container. Fe(CO)5Fe+ 5COPredict and explain what happens to the position of equilibrium when the pressure is decreased. The temperature remains the same. prediction explanation This reaction can be used to produce pure iron. Describe and explain, by referring to the equation, how a sample of pure iron that is free from Fe(CO)5is produced from the equilibrium mixture. Iron reacts with hot concentrated sulfuric acid. The products are iron(sulfate, sulfur dioxide and a liquid that turns anhydrous copper(sulfate blue. Construct the symbol equation for this reaction.
9. Metals  →  9.6. Extraction of metals
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
9. Metals  →  9.4. Reactivity series
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3
shows the apparatus used for the electrolysis of concentrated aqueous sodium chloride using graphite electrodes. power supply + − Label the cathode on . Explain why concentrated aqueous sodium chloride conducts electricity. Name the product formed at the cathode. Chlorine is formed at the anode. Construct the ionic half-equation for the reaction at the anode. Graphite is suitable as an electrode because it conducts electricity. State one other property of graphite that makes it suitable for use as an electrode. State the product formed at the cathode when molten sodium chloride is electrolysed.
4. Electrochemistry  →  4.1. Electrolysis
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4
This question is about alkanes and alkenes. But-1-ene belongs to the alkene homologous series. Members of the same homologous series differ from one member to the next by a –CH2– group and have similar chemical properties. State two other characteristics of a homologous series. shows the displayed formula of but-1-ene. H C C C H H H H H H H C Explain how shows that but-1-ene is an unsaturated compound. Give the structural formula of but-1-ene. Draw the displayed formula of an isomer of but-1-ene. Undecane, C11H24, is present in the kerosene/paraffin fraction from the distillation of petroleum. Give one use of the kerosene/paraffin fraction. When undecane is cracked, shorter hydrocarbon molecules are formed. Construct the symbol equation for a reaction in which undecane is cracked and the only products are butane, propene and ethene. Propane reacts with chlorine to form chloropropane and one other product, X. C3H8 + Cl 2 C3H7Cl + X Name product X. State the essential condition for this reaction. Ethene reacts with bromine at room temperature. shows the displayed formulae of the reactants and product. C H H H H C H C C H + Br Br Br H H Br Calculate the enthalpy change of this reaction in kJ / mol. Use the bond energies in Table 4.1. Table 4.1 type of bond C=C C–H Br–Br C–C C–Br bond energy in kJ / mol enthalpy change = kJ / mol Describe the colour change when a sample of excess ethene is added to a few drops of aqueous bromine. from to
11. Organic chemistry  →  11.5. Alkenes
11. Organic chemistry  →  11.2. Naming organic compounds
11. Organic chemistry  →  11.4. Alkanes
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5
A student adds large pieces of copper(carbonate to dilute hydrochloric acid. The copper(carbonate is in excess. Complete the equation by adding state symbols for the products. CuCO3+ 2HCl CuCl 2( ) + H2O( ) + CO2( ) shows how the mass of the reaction mixture changes with time as the reaction proceeds. 199.0 199.2 199.4 time / min 199.6 199.8 mass of reaction mixture / g 200.0 In another experiment, powdered copper(carbonate is used instead of large pieces of copper(carbonate. All other conditions and the mass of copper(carbonate stay the same. Draw a line on the grid in to show how the mass of the reaction mixture changes with time. The initial experiment is repeated using large pieces of copper(carbonate and hydrochloric acid of a higher concentration. All other conditions stay the same. Describe and explain the difference in rate of reaction when hydrochloric acid of a higher concentration is used. Excess copper(carbonate is added to 22.0 cm3 of 0.500 mol / dm3 hydrochloric acid. Calculate the volume of carbon dioxide released measured at room temperature and pressure. Give your answer to two significant figures. volume of carbon dioxide gas = dm3 Describe the observations made when: • a few drops of aqueous ammonia are added to an aqueous solution containing copper(ions • excess aqueous ammonia is added to an aqueous solution containing copper(ions. An ionic compound of copper has the formula Cu2O. Deduce the oxidation number of copper in Cu2O. Describe how to prepare crystals of ammonium chloride by reacting aqueous ammonia with dilute hydrochloric acid.
9. Metals  →  9.4. Reactivity series
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
4. Electrochemistry  →  4.1. Electrolysis
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6
shows the structures of zinc sulfide and disulfur dichloride. Zinc sulfide has a structure similar to diamond. zinc sulfide zinc atoms sulfur atoms Key: disulfur dichloride Cl S S Cl Explain why zinc sulfide does not conduct electricity. Use the information in . Predict one other physical property of zinc sulfide. Explain why disulfur dichloride has a low melting point. Use the information in . Complete to show the dot-and-cross diagram for the electronic configuration of disulfur dichloride. Show only the outer shell electrons. Cl S S Cl Disulfur dichloride reacts with water as shown. S2Cl 2 + 3H2O 2HCl + H2S + H2SO3 13.5 g of disulfur dichloride is reacted with 8.00 g of water. Show by calculation that water is in excess. Sulfur dioxide is an air pollutant. State one adverse effect of sulfur dioxide in the air. Describe two ways of reducing the emissions of sulfur dioxide in the air.
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
9. Metals  →  9.5. Corrosion of metals
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7
Propanoic acid can be represented by the formula CH3CH2COOH. Propanoic acid reacts with methanol, CH3OH, to produce an ester. Name the ester formed and draw its displayed formula. name displayed formula Propanoic acid is a weak acid. CH3CH2COOH + H2O CH3CH2COO– + H3O+ Explain how this equation shows that: • CH3CH2COOH is an acid by referring to proton transfer • CH3CH2COOH is a weak acid. Propanoic acid reacts with magnesium. Name the two products of this reaction. Magnesium is a solid at room temperature. Describe the motion and separation of the particles in a solid. motion separation shows the simplified structures of two molecules that combine to form a polyamide. H O C O O C N H H H H N O H Complete the diagram in to show the structure of two repeat units of this polyamide. Show all of the atoms and all of the bonds in the linkages. Polyamides are polymers. State the meaning of the term polymer. Polyamides are condensation polymers. State one difference between condensation polymerisation and addition polymerisation.
11. Organic chemistry  →  11.8. Polymers
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