0620_s20_qp_43
A paper of Chemistry, 0620
Questions:
8
Year:
2020
Paper:
4
Variant:
3
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1
The structures of five organic compounds, A, B, C, D and E, are shown. Answer the questions that follow. Each letter may be used once, more than once or not at all. H C H H C A H H C C O O H H C C C C H H H H H H H C H H C B H H C H H H H H C H H C C O O H H H C H H C D E H H C O H H H H Give the letter of the compound that is propan-1-ol. Give the letter of the compound that has the empirical formula CH2. Give the letter of one compound that reacts with bromine in an addition reaction. Give the letter of one compound that reacts with chlorine to form the compound shown. H C H H C Cl H C H H H Give the letters of two compounds that can react with each other to form an ester. and �������������������������������������������������������������� Give the letter of the compound that is in the same homologous series as hex‑1‑ene. Give the letter of one compound that is an acid. Draw a structural isomer of compoundD. Show all of the atoms and all of the bonds.  Some acids are described as weak acids. State the meaning of the term weak acid. weak acid  
11. Organic chemistry  →  11.2. Naming organic compounds
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
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2
Ammonia is manufactured by the Haber process. The equation for the reaction is shown. N2+ 3H22NH3State what is meant by the symbol . State one source of hydrogen used in the manufacture of ammonia. The table shows some data for the production of ammonia. pressure / atm temperature / °C percentage yield of ammonia Deduce the effect on the percentage yield of ammonia of: ● ● increasing the pressure of the reaction ● ● increasing the temperature of the reaction.  Explain, in terms of particles, what happens to the rate of this reaction when the temperature is increased. Ammonia, NH3, is used to produce nitricacid, HNO3. This happens in a three-stage process. Stage1 is a redox reaction. 4NH3 + 5O2 → 4NO + 6H2O Identify what is oxidised in stage1. Give a reason for your answer. substance oxidised reason  In this reaction the predicted yield of NO is 512 g. The actual yield is 384 g. Calculate the percentage yield of NO in this reaction.  percentage yield of NO = The equation for the reaction in stage2 is shown. 2NO + O2 → 2NO2 Which major environmental problem does NO2 cause if it is released into the atmosphere? The equation for the reaction in stage3 is shown. 4NO2 + 2H2O + O2 → 4HNO3 Calculate the volume of O2 gas, at room temperature and pressure (r.t.p.), needed to produce 1260 g of HNO3. Use the following steps. ● ● Calculate the number of moles of HNO3.  moles of HNO3 = ● ● Deduce the number of moles of O2 that reacted.  moles of O2 = ● ● Calculate the volume of O2 gas that reacts at room temperature and pressure (r.t.p.).  volume of O2 gas = dm3  The reaction in stage3 is exothermic. 4NO2 + 2H2O + O2 → 4HNO3 Complete the energy level diagram for this reaction. Include an arrow that clearly shows the energy change during the reaction. energy progress of reaction 4NO2 + 2H2O + O2  
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
6. Chemical reactions  →  6.2. Rate of reaction
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3
Chlorine is in GroupVII of the PeriodicTable. Two isotopes of chlorine are chlorine‑35 and chlorine‑37. State why these two isotopes of chlorine have the same chemical properties. Complete the table to show the number of electrons, neutrons and protons in each atom and ion. number of electrons number of neutrons number of protons 35Cl 37Cl –  Chlorine reacts with aqueous sodium bromide. The equation for the reaction is shown. Cl 2 + 2NaBr → 2NaCl + Br2 State the type of reaction shown. Why is there no reaction between iodine and aqueous sodium bromide? Magnesium reacts with chlorine to form magnesiumchloride. Complete the dot-and-cross diagram to show the electron arrangement of the ions in magnesiumchloride. Give the charges on the ions. The inner shells have been completed. Cl Mg  Hydrogen and chlorine react to form hydrogenchloride gas, as shown in the equation. H2 + Cl 2 → 2HCl This equation can be represented as shown. H–H + Cl –Cl → 2H–Cl Some bond energies are shown in the table. bond bond energy in kJ / mol H–H Cl –Cl H–Cl Calculate the energy change for the reaction between hydrogen and chlorine, using the following steps. ● ● Calculate the energy needed to break the bonds.  kJ ● ● Calculate the energy released when bonds are formed.  kJ ● ● Calculate the energy change for the reaction.  kJ / mol  
11. Organic chemistry  →  11.4. Alkanes
5. Chemical energetics  →  5.1. Exothermic and endothermic reactions
2. Atoms, elements and compounds  →  2.3. Isotopes
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4
Filtration and chlorination are two stages in water treatment. State the purpose of each stage. filtration chlorination  A student uses anhydrous copper(sulfate to test for the presence of water. What colour change is seen if water is present? from to ����������������������������������������������������������� The purity of a sample of water can be assessed by measuring its boiling point. How is the boiling point of water affected by impurities? Chromatography can be used to test the purity of substances. The diagram shows the chromatogram of a coloured substance. X solvent front start line How does this chromatogram show that this substance is not pure? Draw a circle round the correct Rf value for the spot labelled X. 0.2 0.4 0.8 1.2 State how a colourless substance can be made visible on a chromatogram. 
10. Chemistry of the environment  →  10.1. Water
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5
Complete the table about solids, liquids and gases. particle separation particle arrangement type of motion solid regular vibrate only liquid touching random gas apart random  The graph shows the change in temperature as a sample of a gas is cooled. temperature time A B Name the change of state taking place between A and B. A bottle of liquid perfume is left open at the front of a room. After some time, the perfume is smelt at the back of the room. Name the two physical processes taking place.  
1. States of matter  →  1.1. Solids, liquids and gases
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7
Aluminium is extracted by electrolysis. Iron is extracted from its ore by reduction with carbon. What is meant by the term electrolysis? Name the main ore of aluminium. Explain why aluminium cannot be extracted by reduction with carbon. Describe the role of cryolite in the extraction of aluminium by electrolysis. Name the product formed at the positive electrode. Write the ionic half-equation for the reaction at the negative electrode. Aluminium is used in overhead electricity cables. Give two properties of aluminium that make it suitable for use in overhead electricity cables.  Iron is a transition element. Iron forms hydrated iron(oxide when it rusts. Write a word equation to represent the formation of rust. Give two ways in which the properties of transition elements differ from the properties of GroupI metals.  
9. Metals  →  9.6. Extraction of metals
9. Metals  →  9.2. Uses of metals
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8
Part of the synthetic polymer, nylon, is shown in the diagram. C O C O C C O O N H N H N H N H C O Circle one amide linkage on the diagram. Complete the structures of the two monomers that react to form nylon.  Name the other product formed when nylon is produced. Items made from nylon are often disposed of by burying them in the ground. This is called landfill. Why is the disposal of nylon using landfill a problem? Give the name of a natural polymer. 
11. Organic chemistry  →  11.8. Polymers
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