0620_w23_qp_43
A paper of Chemistry, 0620
Questions:
6
Year:
2023
Paper:
4
Variant:
3
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1
A list of substances is shown. barium nitrate carbon monoxide hydrated cobalt(chloride copper(oxide anhydrous copper(sulfate ethane potassium iodide propene sodium bromide sulfur dioxide zinc oxide Answer the following questions using only the substances from the list. Each substance may be used once, more than once or not at all. Give the name of the substance that: gives a lilac colour in a flame test forms a cream precipitate when its aqueous solution reacts with acidified aqueous silvernitrate is an acidic oxide is an unsaturated hydrocarbon is a product of incomplete combustion of fossil fuels is used to test for the presence of water. 
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
10. Chemistry of the environment  →  10.1. Water
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2
Table2.1 gives information about particles A, B, C, D, E and F. Table 2.1 particle number of electrons number of neutrons number of protons A B C D E F Give the letters of all the particles which are: atoms ions with a charge of 2– cations. State the atomic number of A. Determine the number of nucleons in D. State the electronic configuration of D. State the group number of F. State the period number of B. 
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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This question is about nitrogen and some of its compounds. Nitrogen is converted into ammonia, NH3, in the Haber process. Nitrogen is obtained from air. State the percentage of nitrogen in clean, dry air. State the source of hydrogen for the Haber process. Complete the dot-and-cross diagram in Fig.3.1 for a molecule of ammonia. Show the outer shell electrons only. N H H H  Write a chemical equation for the reaction occurring in the Haber process and give the typical reaction conditions. Include units where appropriate. chemical equation reaction conditions: temperature pressure catalyst  Ammonia is converted into nitricacid. The first stage of this conversion uses a catalyst and occurs at a temperature of 900 °C and a pressure of 5atmospheres. 4NH3+ 5O24NO+ 6H2OThe forward reaction is exothermic. Suggest which of the following elements is most likely to be used as a catalyst. Draw a circle around your answer. calcium lead platinum sodium sulfur State the oxidation number of nitrogen in: NH3 NO  Use your answer to to explain whether the nitrogen in ammonia undergoes oxidation or reduction. Complete Table3.1 using the words increases, decreases or no change. Table 3.1 effect on the equilibrium yield of NOeffect on the rate of the forward reaction decreasing the pressure decreasing the temperature decreases removing the catalyst decreases  Decreasing the temperature causes the rate of the forward reaction to decrease. Explain, using collision theory, why the rate of the reaction is slower at the decreased temperature. In the second stage, nitric acid is produced. Balance the symbol equation for this reaction. NO + O2 + H2O → HNO3 
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
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4
This question is about sulfuricacid and salts that are made from sulfuricacid. Zinc reacts with dilute sulfuricacid. Aqueous zincsulfate is one of the products. Powdered zinc is added to dilute sulfuricacid. The mixture is stirred. More zinc is added, with stirring, until the zinc is in excess. Zn+ H2SO4→ ZnSO4+ H2The mixture is then filtered. Name the limiting reactant. State two observations that indicate the zinc is in excess.  Name the filtrate. Name two compounds which both react with dilute sulfuric acid to produce aqueous zincsulfate.  Zincsulfate crystals are produced by heating aqueous zincsulfate until a saturated solution is formed. When the saturated solution cools down, crystals of zincsulfate start to form. State what is meant by the term saturated solution. Explain why crystals form when the saturated solution cools down. Nickel(sulfate crystals contain water of crystallisation. When nickel(sulfate crystals, NiSO4•xH2O, are heated, they give off water. NiSO4•xH2O→ NiSO4+ xH2OA student carries out an experiment to determine the value of x in NiSO4•xH2O. step 1 Nickel(sulfate crystals are weighed. step 2 Nickel(sulfate crystals are heated. step 3 The remaining solid is allowed to cool and is then weighed. step 4 The remaining solid is heated again, allowed to cool and is then weighed. step 5 Step4 is repeated until there is no change in mass. State the term used to describe crystals that contain water of crystallisation. State why step4 is repeated until there is no change in mass. In an experiment, 0.454 g of nickel(sulfate crystals, NiSO4•xH2O, is used. The mass of anhydrous nickel(sulfate, NiSO4, remaining is 0.310 g. [Mr: NiSO4, 155; H2O, 18] Determine the value of x in NiSO4•xH2O. Use the following steps. ● Calculate the number of moles of NiSO4 remaining.  moles of NiSO4 = ● Calculate the mass of H2O given off.  mass of H2O = g ● Calculate the number of moles of H2O given off.  moles of H2O =
9. Metals  →  9.4. Reactivity series
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
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5
This question is about iron. Describe the bonding in a metallic element such as iron. You may include a labelled diagram as part of your answer. Explain why iron conducts electricity when it is solid. Iron is extracted from hematite in the blast furnace as shown in Fig.5.1. waste gases coke, hematite, limestone molten iron slag air air Give two reasons why coke is added to the blast furnace.  Explain how limestone removes the impurities in the hematite. Hematite contains iron(oxide. Write a symbol equation for the conversion of iron(oxide to iron in the blast furnace. Suggest why the iron produced in the blast furnace is molten. Most iron is converted into steel. Steel is an alloy. Steel is more useful than pure iron because it is harder and stronger. Explain why the structure of alloys causes them to be harder and stronger than pure metals. You may include a diagram as part of your answer. Iron forms rust. Rusting is prevented by coating iron with zinc. Name the substances that react with iron to form rust. Name the process in which zinc is used to coat iron to prevent rusting. Explain how the coating of zinc prevents rusting if the zinc is not scratched. When zinc is scratched the iron becomes exposed. Explain how the zinc continues to prevent rusting. 
9. Metals  →  9.6. Extraction of metals
9. Metals  →  9.5. Corrosion of metals
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Esters are members of a homologous series of organic compounds. Give two characteristics that are the same for all members of a homologous series.  EsterX has the structure shown in Fig.6.1. O O C C H H H H H C C C H H H H H Name esterX. Ester Y has the structural formula HCOOCH2CH2CH3. Name the alcohol and the carboxylic acid used to make esterY. alcohol carboxylic acid  State the molecular formula of esterY. EsterZ has the molecular formula C4H8O2. State the empirical formula of esterZ. Polymers containing ester linkages are known as polyesters. Polyamides are another type of polymer. Nylon is a polyamide. The structure of nylon is shown in Fig.6.2. C O C O N H N H State the term used to describe the type of polymerisation used to produce polyesters and polyamides. Complete Fig.6.3 to show the structures of the monomers used to produce nylon. Show all of the atoms and all of the bonds.  Naturally occurring polyamides are found in food. State the name given to naturally occurring polyamides. Name the type of monomer which forms naturally occurring polyamides. 
11. Organic chemistry  →  11.8. Polymers
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