5070_w19_qp_21
A paper of Chemistry, 5070
Questions:
9
Year:
2019
Paper:
2
Variant:
1
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1
The diagram shows part of the Periodic Table. B C Mg Al Si P V Fe Cu Zn Answer the questions using only the elements shown in the diagram. Each element may be used once, more than once or not at all. Write the symbol for an element which: forms a stable ion by gaining three electrons is extracted from haematite forms an ion which gives a red-brown precipitate on addition of aqueous ammonia has chemical properties similar to those of calcium can have lubricating properties.
8. The Periodic Table  →  8.1. Arrangement of elements
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Sodium is a metal. State two physical properties of sodium which are different from most other metals. Complete the electronic configuration of a sodium atom. Show all electrons. Na The equation shows the reaction of sodium with water. 2Na+ 2H2O2NaOH+ H2Calculate the minimum mass of sodium, in grams, needed to produce 300 cm3 of hydrogen gas at room temperature and pressure. Give your answer to three significant figures. mass of sodium g Sodium reacts with oxygen to form the ionic solid sodium oxide, Na2O. Explain, in terms of movement of electrons, how Na2O is formed by the reaction of sodium with oxygen. Sodium chloride is an ionic compound which is a solid at room temperature. It is soluble in water. Suggest one other physical property of sodium chloride. State the products formed at the anode and cathode when concentrated aqueous sodium chloride is electrolysed. product at anode product at cathode Describe a test for chloride ions. test observation
4. Electrochemistry  →  4.1. Electrolysis
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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Water can be removed from aqueous copper(sulfate by distillation. Describe how and explain why water can be separated from aqueous copper(sulfate by distillation. In your answer include a description of distillation. You may draw a labelled diagram. Copper(sulfate can be prepared by heating excess copper(oxide with dilute sulfuric acid. CuO+ H2SO4CuSO4+ H2OWhat method is used to separate excess copper(oxide from the reaction mixture? A copper compound contains 21.09% copper, 43.82% caesium and 35.09% chlorine by mass. Use this information to deduce the empirical formula of this copper compound. empirical formula
4. Electrochemistry  →  4.1. Electrolysis
10. Chemistry of the environment  →  10.1. Water
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
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This question is about compounds containing chlorine. The equation shows the reaction of aqueous methanol with hydrochloric acid. CH3OH+ HCl CH3Cl + H2OThe progress of this reaction can be followed by taking small samples of the reaction mixture every hour and determining the concentration of hydrochloric acid. Describe a practical method by which the concentration of hydrochloric acid can be determined in a sample. The graph shows how the concentration of hydrochloric acid changes as the reaction proceeds. 0.20 0.40 time in hours concentration of HCl in mol / dm3 0.60 0.80 1.00 1.20 1.40 1.60 1.80 A B C D Deduce the concentration of hydrochloric acid four hours from the start of the experiment. mol / dm3 At which point on the graph, A, B, C or D, is the rate of reaction fastest? Give a reason for your answer by referring to the graph. Describe and explain, using ideas about collisions between particles, how the rate of a reaction changes when the temperature is decreased. All other conditions stay the same. Describe the effect of hydrochloric acid on Universal Indicator paper. Name a metal chloride that is insoluble in water. Chlorofluorocarbons (CFCs) diffuse into the atmosphere. Describe the effect of CFCs on the atmosphere and explain why this is a problem. effect explanation
6. Chemical reactions  →  6.2. Rate of reaction
9. Metals  →  9.4. Reactivity series
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The table shows some properties of four Group VII elements. element melting point in °C boiling point in °C density of liquid at boiling point in g / cm3 colour chlorine −101 −35 light green bromine −7 3.12 red-brown iodine 4.93 grey-black astatine 6.35 Complete the table by estimating • the boiling point of bromine • the density of liquid chlorine at its boiling point. Use the information in the table to suggest the colour of astatine. Explain why chlorine is used in water treatment. Chlorine reacts with aqueous potassium iodide. The products are aqueous potassium chloride and aqueous iodine. Construct the ionic equation for this reaction. Explain why potassium chloride does not react with iodine. Hydrated nickel(chloride has the formula NiCl 2.xH2O. It has a relative formula mass of 238. Calculate the value of x in this formula. [The relative atomic mass of nickel, Ni, is 59] x =
8. The Periodic Table  →  8.3. Group VII properties
10. Chemistry of the environment  →  10.1. Water
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6
Ethanoic acid, CH3COOH, is a weak acid. What is the meaning of the term weak when applied to acids? Ethanoic acid is solid at 16.0 °C. Describe the arrangement and movement of the particles in a solid. arrangement movement The melting point of ethanoic acid is 16.7 °C. The boiling point of ethanoic acid is 118.0 °C. Deduce the physical state of ethanoic acid at 130.0 °C. Explain your answer. The equation for the reaction of ethanoic acid with sodium carbonate is shown. 2CH3COOH + Na2CO3 2CH3COONa + CO2 + H2O A student added 3.18 g of sodium carbonate to 224 cm3 of 0.250 mol / dm3 ethanoic acid. Show by calculation that sodium carbonate is in excess. Calcium reacts with ethanoic acid. The products are calcium ethanoate and hydrogen. Construct the equation for this reaction. Ethanoic acid reacts with butanol, C4H9OH, to produce an ester. Name the ester formed when ethanoic acid reacts with butanol. Draw the structure of this ester.
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
11. Organic chemistry  →  11.7. Carboxylic acids
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Hydrogen can be produced when steam and carbon monoxide are passed over a catalyst. H2O+ COCO2+ H2ΔH = − 41 kJ / mol The temperature of the equilibrium mixture is decreased. The pressure on the equilibrium mixture is kept constant. Describe how and explain why the position of equilibrium changes. The pressure on the equilibrium mixture is increased. The temperature of the equilibrium mixture is kept constant. Explain why the change in pressure has no effect on this equilibrium. Hydrogen is also produced when steam is passed over hot coke . This reaction is endothermic. H2O+ CCO+ H2On the axes below draw a labelled energy profile diagram for the reaction to show: • the reactants and products • the enthalpy change for the reaction • the activation energy of the reaction. progress of reaction energy The mixture of gases produced when steam is passed over hot coke also contains hydrogen sulfide, H2S, as an impurity. This can be removed by reacting the gas with moist iron(hydroxide. Complete the equation for this reaction. … Fe(OH)3 + …. H2S Fe2S3 + …. H2O Fossil fuels contain small amounts of sulfur. Describe how the combustion of fossil fuels leads to the formation of acid rain. Describe one effect of acid rain on buildings.
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
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Silicon is an element in Group IV of the Periodic Table. One of the isotopes of silicon is: 14Si Deduce the number of electrons, neutrons and protons in one atom of this isotope of silicon. number of electrons number of neutrons number of protons Silicon reacts with nitrogen when heated to produce silicon nitride, Si3N4. Construct the equation for this reaction. The structure of silicon dioxide is shown. silicon atom oxygen atom Describe two similarities in the structures of silicon dioxide and diamond. Explain why silicon dioxide has a high melting point. The structure of a compound of silicon is shown. O H H H H H H H C C O Si H C H C H H H Deduce the molecular formula of this compound. Draw a ‘dot-and-cross’ diagram for a silicon(chloride molecule, SiCl 4. Only include the outer shell electrons.
2. Atoms, elements and compounds  →  2.6. Giant covalent structures
2. Atoms, elements and compounds  →  2.2. Atomic structure and the Periodic Table
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9
This question is about polymers. Polyesters and polyamides are both polymers formed by condensation reactions. What is meant by the term condensation reaction? The partial structure of a polyester is shown. O O C O O C O O C O O C On the diagram, draw a circle around an ester linkage. Draw the structures of the two monomers used to produce this polymer. Terylene is a polyester. State one common use of Terylene. The structure of the amino acid threonine is shown. H C CH3 C H OH COOH H2N Threonine can be polymerised. Explain, by referring to the groups present, why polymers with different linkages can be formed from threonine. Polyis made from ethene monomers. Draw the structure of ethene, showing all of the atoms and all of the bonds. Polyis a non-biodegradable plastic. What is meant by the term non-biodegradable? Describe one pollution problem caused by the disposal of non-biodegradable plastics.
11. Organic chemistry  →  11.8. Polymers
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