0620_s22_qp_43
A paper of Chemistry, 0620
Questions:
6
Year:
2022
Paper:
4
Variant:
3
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1
A list of substances is shown. aluminium oxide carbon dioxide carbon monoxide chlorine copper glucose iron(oxide limestone nitrogen oxygen Answer the questions using the substances in the list. Each substance may be used once, more than once or not at all. State which substance is: a product of respiration the main constituent of hematite an element which has a sulfate that is used to test for water a colourless toxic gas a reactant in fermentation a reducing agent in the extraction of iron a conductor of electricity when solid a gas that is approximately 21% of clean, dry air. 
10. Chemistry of the environment  →  10.1. Water
9. Metals  →  9.6. Extraction of metals
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2
32S 16 and 33S 16 are isotopes of sulfur. Use your knowledge of protons, neutrons and electrons to answer the following questions. Describe how these isotopes of sulfur are the same and how they are different. same different  Explain why each of these isotopes have an overall charge of zero. Explain why both isotopes have the same chemical properties. Sulfide ions, S2–, have the electronic structure 2,8,8. Explain why sulfide ions have a charge of 2–. Give the formula of: ● an anion which has the same electronic structure as S2– ● a cation which has the same electronic structure as S2–.  
2. Atoms, elements and compounds  →  2.3. Isotopes
8. The Periodic Table  →  8.1. Arrangement of elements
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This question is about nitrogen and compounds of nitrogen. Nitrogen molecules have the formula N2. Some properties of nitrogen are shown: ● melting point of –210 °C ● boiling point of –196 °C ● non-conductor of electricity when solid ● insoluble in water. Name the type of bonding between the atoms in an N2 molecule. Explain, in terms of attractive forces between particles, why nitrogen has a low melting point. Explain why nitrogen does not conduct electricity. Nitrogen reacts with hydrogen to form ammonia, NH3, in the Haber process. State the essential conditions in the Haber process. Write an equation for the chemical reaction. Ammonia is made in the laboratory by heating ammonium chloride with calciumhydroxide. Balance the chemical equation for the reaction. NH4Cl + Ca(OH)2 → NH3 + CaCl 2 + H2O Hydrazine, N2H4, is another compound that contains nitrogen and hydrogen. Complete the dot-and-cross diagram to show the electron arrangement in a molecule of hydrazine. Show outer electrons only. N H H N H H  Ammonia and hydrazine are weak bases. The chemical equation for the reaction between one molecule of ammonia and one molecule of water is shown. NH3 + H2O NH4 + + OH– State the meaning of the term base. Write a chemical equation for the reaction between one molecule of hydrazine, N2H4, and one molecule of water. 
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
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4
Ethanol is made industrially by the reaction of ethene with steam. The reaction occurs at a temperature of 300 °C and a pressure of 60 atmospheres. C2H4+ H2OC2H5OHA catalyst is used in this reaction. The forward reaction is exothermic. State what is meant by the term catalyst. 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 C2H5OHincreasing the temperature decreasing the pressure  Ethanol is a member of the alcohol homologous series. Members of the same homologous series have the same general formula. State the general formula of alcohols. State two general characteristics, other than the same general formula, of all homologous series.  One alcohol containing three carbon atoms is propan-1-ol. Draw the structure of one other alcohol containing three carbon atoms. Show all of the atoms and all of the bonds. Name the alcohol you have drawn. name  When alcohols react with carboxylic acids, esters are produced. The structure of ester X is shown. O O H C H H C H H C H H C H H H H H C C Name ester X. Give the name of the alcohol and the carboxylic acid that react together to produce esterX. alcohol carboxylic acid  Ester Y has the following composition by mass: C, 58.82%; H, 9.80%; O, 31.37%. Calculate the empirical formula of ester Y.  empirical formula = Ester Z has the empirical formula C3H6O and a relative molecular mass of 116. Calculate the molecular formula of ester Z.  molecular formula = 
11. Organic chemistry  →  11.6. Alcohols
11. Organic chemistry  →  11.1. Formulae, functional groups and terminology
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This question is about copper and its compounds. Describe the bonding in a metallic element such as copper. You may include a diagram as part of your answer. A metal spoon is electroplated with copper. State what is used as: the positive electrode the negative electrode the electrolyte.  The formula for crystals of hydrated copper(sulfate is CuSO4•5H2O. Hydrated copper(sulfate is made by reacting copper(oxide with dilute sulfuricacid. The overall equation is shown. CuO + H2SO4 + 4H2O → CuSO4•5H2O The crystals are made using the following steps: step 1 50.0 cm3 of 0.200 mol / dm3 dilute sulfuric acid is heated in a beaker. Powdered copper(oxide is added until the copper(oxide is in excess. Aqueous copper(sulfate is formed. step 2 The excess copper(oxide is separated from the aqueous copper(sulfate. step 3 The aqueous copper(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. Calculate the maximum mass of copper(sulfate crystals, CuSO4•5H2O, that can form using the following steps. ● Calculate the number of moles of H2SO4 in 50.0 cm3 of 0.200 mol / dm3 H2SO4.  mol ● Deduce the number of moles of CuSO4•5H2O that can form.  mol ● The Mr of CuSO4•5H2O is 250. Calculate the maximum mass of CuSO4•5H2O that can form.  g  State one observation that indicates the copper(oxide is in excess in step1. Step 1 is repeated without heating the dilute sulfuricacid. All other conditions are kept the same. The rate of reaction decreases. Give a reason why the rate of reaction decreases. Explain your answer in terms of particles. Name a substance, other than copper(oxide, that can be added to dilute sulfuricacid to produce copper(sulfate in step 1. Name the process used to separate excess copper(oxide from aqueous copper(sulfate in step2. Suggest what is meant by the term saturated solution in step3. The phrase ‘heating to dryness’ means heating until no more water is given off. Explain why aqueous copper(sulfate is not heated to dryness in step3. 
4. Electrochemistry  →  4.1. Electrolysis
9. Metals  →  9.4. Reactivity series
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6
The Periodic Table can be used to classify elements. The GroupI metals react with cold water. Transition elements do not react with cold water. Describe two other differences in the chemical properties between GroupI metals and transition elements.  Describe the observations when potassium is added to cold water. Write a balanced equation for the reaction. Include state symbols. observations equation  Transition elements are stronger than GroupI metals. Describe two other differences in the physical properties of GroupI metals and transition elements.  Some GroupVII elements react with aqueous solutions containing halide ions. When aqueous bromine is added to aqueous potassium iodide a reaction occurs. The ionic half-equations for the reaction are shown. Br2+ 2e– → 2Br –2I–→ I2+ 2e– Describe the colour change of the solution. original colour of potassium iodide solution final colour of reaction mixture  State the name of the general term given to the type of reaction in which electrons are transferred from one species to another. Identify the oxidising agent in this reaction. Give a reason for your answer. oxidising agent reason  Use the key to complete the table to show the results of adding aqueous halogens to aqueous solutions of halides. One has been completed for you. halides key ✓ = reaction ✗ = no reaction KCl KBrKIhalogens Cl 2Br2✓ I2 
8. The Periodic Table  →  8.3. Group VII properties
9. Metals  →  9.4. Reactivity series
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