0620_s22_qp_41
A paper of Chemistry, 0620
Questions:
7
Year:
2022
Paper:
4
Variant:
1
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1
A list of substances is shown. aluminium oxide carbon dioxide chlorine diamond ethanol glucose iron(oxide limestone nitrogen oxygen Answer the questions using the list of substances. Each substance may be used once, more than once or not at all. State which of the substances: is a reactant in photosynthesis is the main constituent of bauxite are two products of fermentation and is used as a fuel is a gas used to convert iron into steel is a greenhouse gas is a gas that is approximately 78% of clean, dry air is a form of carbon. 
10. Chemistry of the environment  →  10.1. Water
9. Metals  →  9.6. Extraction of metals
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Atoms are made of protons, neutrons and electrons. Atoms of the same element are known as isotopes. Complete the table. particle relative charge relative mass electron neutron proton +1  24Mg and 25Mg are isotopes of magnesium. Complete the table to show the numbers of electrons, neutrons and protons in these isotopes of magnesium. isotope number of electrons number of neutrons number of protons 24Mg 25Mg  Explain why magnesium ions have a charge of 2+. Mg2+ ions have the electronic structure 2,8. Give the formula of the following particles which have the same electronic structure as Mg2+ ions. ● a cation (positive ion) ● an anion (negative ion) ● an atom  
2. Atoms, elements and compounds  →  2.2. Atomic structure and the Periodic Table
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This question is about sodium and compounds of sodium. Describe the bonding in a metallic element such as sodium. You may include a diagram as part of your answer. Describe how solid sodium conducts electricity. Some properties of sodium chloride are shown: ● melting point of 801 °C ● non-conductor of electricity when solid ● conductor of electricity when molten ● soluble in water. Name the type of bonding in sodium chloride. Explain why sodium chloride conducts electricity when molten. A student determines the concentration of a solution of dilute sulfuricacid, H2SO4, by titration with aqueous sodiumhydroxide, NaOH. step 1 25.0 cm3 of 0.200 mol / dm3 NaOH is transferred into a conical flask. step 2 Three drops of methyl orange indicator are added to the conical flask. step 3 A burette is filled with H2SO4. step 4 The acid in the burette is added to the conical flask until the indicator changes colour. The volume of acid is recorded. This process is known as titration. step 5 The titration is repeated several times until a suitable number of results is obtained. Name the piece of apparatus used to measure exactly 25.0 cm3 of 0.200 mol / dm3 NaOH in step1. State the colour change of the methyl orange indicator in step4. from to State how the student decides that a suitable number of results have been obtained. 20.0 cm3 of H2SO4 reacts with 25.0 cm3 of 0.200 mol / dm3 NaOH. The equation for the reaction is shown. H2SO4 + 2NaOH → Na2SO4 + 2H2O Calculate the concentration of H2SO4 using the following steps. ● Calculate the number of moles in 25.0 cm3 of 0.200 mol / dm3 NaOH.  mol ● Determine the number of moles of H2SO4 that react with the NaOH.  mol ● Calculate the concentration of H2SO4.  mol / dm3  
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
4. Electrochemistry  →  4.1. Electrolysis
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This question is about compounds of sulfur. Sulfuricacid, H2SO4, is manufactured using the Contact process. This manufacture involves four stages. stage 1 Molten sulfur burns in air to produce sulfurdioxide. stage 2 Sulfurdioxide reacts with oxygen to form sulfurtrioxide. stage 3 Sulfurtrioxide combines with concentrated sulfuricacid to form oleum, H2S2O7. stage 4 Oleum reacts to form concentrated sulfuricacid. Write a chemical equation for the reaction occurring in stage1. State the essential conditions that are necessary for stage2. Write an equation for the chemical reaction that occurs. Write a chemical equation for the reaction occurring in stage3. Name the substance that reacts with oleum in stage4. Hydrogensulfide has the formula H2S. Complete the dot-and-cross diagram to show the electron arrangement in a molecule of hydrogensulfide. Show outer shell electrons only. S H H  Balance the chemical equation for the reaction of hydrogensulfide with sulfur dioxide shown. H2S + SO2 → S + H2O 
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
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Ethanoicacid is manufactured by the reaction of methanol with carbonmonoxide. An equilibrium mixture is produced. CH3OH+ COCH3COOHState two characteristics of an equilibrium.  The purpose of the industrial process is to produce a high yield of ethanoicacid at a high rate of reaction. The manufacture is carried out at a temperature of 300 °C. The forward reaction is exothermic. Use this information to state why the manufacture is not carried out at temperatures: ● below 300 °C ● above 300 °C.  Complete the table using only the words increases, decreases or no change. effect on the rate of the forward reaction effect on the equilibrium yield of CH3COOHadding a catalyst no change decreasing the pressure  Suggest which of the following metals is a suitable catalyst for the reaction. Give a reason for your answer. aluminium calcium cobalt magnesium potassium suitable catalyst reason  Ethanoicacid is a member of the homologous series of carboxylic acids. State the general formula of this homologous series. Draw the structure of the carboxylic acid containing three carbon atoms. Show all of the atoms and all of the bonds.  When carboxylic acids react with alcohols, esters are produced. The formula of ester X is CH3CH2CH2COOCH3. Name ester X. Give the name of the carboxylic acid and the alcohol that react together to produce esterX. carboxylic acid alcohol  Ester Y has the following composition by mass: C, 48.65%; H, 8.11%; O, 43.24%. Calculate the empirical formula of ester Y.  empirical formula = Ester Z has the empirical formula C2H4O and a relative molecular mass of 88. Determine the molecular formula of ester Z.  molecular formula = 
11. Organic chemistry  →  11.7. Carboxylic acids
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This question is about zinc and its compounds. Zinc is extracted from its ore which is mainly zincsulfide, ZnS. The steps for this extraction are shown. step 1 Zinc sulfide is converted into zinc oxide. step 2 The zincoxide is then reduced to zinc in a furnace. The zinc formed becomes a gas. step 3 The zinc gas is cooled to form molten zinc. Name the ore of zinc, which is mainly zincsulfide. Describe how zincsulfide is converted into zincoxide in step 1. Name the reducing agent used in step2. Explain why the zinc forms a gas in step2 inside the furnace. State the name of the physical change occurring when zinc gas is converted into molten zinc. Zinc sulfate crystals, ZnSO4•7H2O, are hydrated. Zinc sulfate crystals are made by reacting zinc carbonate with dilute sulfuric acid. The equation for the overall process is shown. ZnCO3 + H2SO4 + 6H2O → ZnSO4•7H2O + CO2 step 1 Large pieces of solid zinc carbonate are added to dilute sulfuric acid until the zinc carbonate is in excess. This forms aqueous zinc sulfate. step 2 The excess zinc carbonate is separated from the aqueous zinc sulfate. step 3 The aqueous zinc sulfate is heated until a saturated solution is formed. step 4 The saturated solution is allowed to cool and crystallise. step 5 The crystals are removed and dried. In step1, zinccarbonate is in excess when no more zinccarbonate dissolves. State one other observation that indicates the zinccarbonate is in excess in step1. Name a different substance, other than zinc carbonate, that can be added to dilute sulfuricacid to produce aqueous zincsulfate in step1. Step1 is repeated using powdered zinccarbonate instead of large pieces. All other conditions are kept the same. The rate of reaction increases. Give a reason why the rate of reaction increases. Explain your answer in terms of particles. Suggest what is observed when the solution is saturated in step3. The formula of zincsulfate crystals is ZnSO4•7H2O. Give the formula of the solid formed if the crystals are heated to dryness in step3. 
9. Metals  →  9.4. Reactivity series
9. Metals  →  9.5. Corrosion of metals
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The Periodic Table can be used to classify elements. GroupI elements react with cold water to form alkaline solutions. Place the GroupI elements caesium, lithium, potassium, rubidium and sodium in their order of reactivity with water. Put the most reactive element first. most reactive least reactive  Name the alkaline solution formed when caesium reacts with cold water. GroupI elements have lower melting points than transition elements. Describe one other difference in the physical properties of Group I elements and transition elements. GroupVII elements are known as the halogens. Astatine is below iodine in GroupVII. Predict the physical state of astatine at room temperature and pressure. Some GroupVII elements react with aqueous solutions containing halide ions. When aqueous chlorine is added to aqueous potassium bromide a reaction occurs. The ionic half-equations for the reaction are shown. Cl 2+ 2e– → 2Cl –2Br –→ Br2+ 2e– Describe the colour change of the solution. original colour of potassium bromide solution final colour of reaction mixture  Identify the species that is oxidised. Explain your decision. species oxidised explanation  Bromine monochloride, BrCl, is made by the reaction between bromine and chlorine. The chemical equation is shown. Br2+ Cl 2→ 2BrCl bond bond energy in kJ / mol Br–Br Cl –Cl Br–Cl Calculate the overall energy change for the reaction using bond energies. Use the following steps. ● Calculate the total amount of energy required to break the bonds in 1mole of Br2and 1mole of Cl 2.  kJ ● Calculate the total amount of energy released when the bonds in 2 moles of BrCl are formed.  kJ ● Calculate the overall energy change for the reaction.  kJ / mol  
8. The Periodic Table  →  8.3. Group VII properties
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