0620_m21_qp_32
A paper of Chemistry, 0620
Questions:
8
Year:
2021
Paper:
3
Variant:
2
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1
The diagram shows part of the Periodic Table. I II III IV V VI VII VIII Mg Al Ar Cl Br I C N O F Ca Cr Fe Cu Zn Pt K Answer the following questions using only the symbols of the elements in the diagram. Each symbol may be used once, more than once or not at all. Give the symbol of the element that: is extracted from bauxite forms 21% of clean, dry air forms an oxide which contributes to acid rain forms an aqueous ion that gives a red-brown precipitate on addition of aqueous sodiumhydroxide has an atom with a complete outer electron shell. 
8. The Periodic Table  →  8.1. Arrangement of elements
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The table shows the mass of some of the ions in a 1000 cm3 sample of sea water. name of ion formula of ion mass of ion in 1000 cm3 of sea water / mg bromide Br – calcium Ca2+ chloride Cl – 18 980 hydrogencarbonate HCO3 – magnesium Mg2+ metaborate B3O6 3– K+ sodium Na+ 10 556 strontium Sr2+ SO4 2– Answer these questions using only the information in the table. State which negative ion has the lowest mass in 1000 cm3 of sea water. Give the formulae of the ions in potassiumsulfate. and Calculate the mass of calcium ions in 200 cm3 of this sample of sea water.  mass = mg A sample of this sea water is evaporated. State the name of the compound which is present in the greatest quantity when this sample is evaporated. Give the name of the ion which reacts with aqueous silvernitrate to give a cream precipitate. The B3O6 3– ion can be converted to boric acid, H3BO3. Boricacid is also produced when borontrichloride, BCl 3, reacts with water. Complete the equation for this reaction. BCl 3 + H2O → H3BO3 + HCl  The symbol of a strontium ion is shown. 87Sr2+ Deduce the number of electrons, protons and neutrons in one atom of this strontium ion. number of electrons number of protons number of neutrons  Some isotopes of strontium are radioactive. Give one medical use of radioactive isotopes. The isotope 235U is also radioactive. State the major use of this isotope of uranium. 
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
6. Chemical reactions  →  6.4. Redox
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The table shows some properties of four halogens. element melting point in °C boiling point in °C density of liquid at melting point in g / cm3 fluorine –220 –188 chlorine –101 1.56 bromine –7 3.12 iodine 4.93 Complete the table by predicting: ● the boiling point of chlorine ● the density of fluorine at its melting point.  Describe the trend in the melting points of the halogens down the group. Deduce the physical state of iodine at 130 °C. Explain your answer. Give the electronic structure of a fluorine atom. Explain why a fluoride ion has a single negative charge. Magnesium reacts with excess fluorine to produce magnesium fluoride. When 2.40 g of magnesium is reacted, 6.20 g of magnesiumfluoride is produced. Calculate the mass of magnesium needed to produce 1.24 g of magnesiumfluoride.  mass of magnesium = g 
8. The Periodic Table  →  8.3. Group VII properties
10. Chemistry of the environment  →  10.1. Water
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A student investigates the reaction of magnesium powder with dilute hydrochloric acid. The magnesium is in excess. Mg + 2HCl → MgCl 2 + H2 The rate of reaction can be found by measuring the increase in volume of hydrogen with time. The results are shown on the graph. time / s volume of hydrogen / cm3 Deduce the time taken for the reaction to finish.  time taken = s The experiment is repeated using dilute hydrochloricacid of a lower concentration. Draw a line on the grid to show how the volume of hydrogen changes with time using dilute hydrochloricacid of a lower concentration. All other conditions stay the same. Describe the effect each of the following has on the rate of reaction of magnesium with hydrochloricacid. ● The temperature is increased. All other conditions stay the same. ● Magnesium ribbon is used instead of magnesium powder. All other conditions stay the same.  Hydrochloricacid reacts with calciumcarbonate. Name the products of this reaction and give the observations. products observations  
6. Chemical reactions  →  6.2. Rate of reaction
9. Metals  →  9.4. Reactivity series
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This question is about sulfur and compounds of sulfur. Sulfur is a non-metal. Describe three physical properties which are typical of non-metals.  Name one source of sulfur. When carbon is heated with sulfur, carbondisulfide, CS2, is produced. C + 2S → CS2 Complete the energy level diagram for the production of carbondisulfide by writing these formulae on the diagram: ● C + 2S ● CS2. energy progress of reaction  Explain, using information on the energy level diagram, how you know that this reaction is endothermic. Carbondisulfide is a liquid at room temperature. Describe the separation and motion of the particles in carbondisulfide liquid. separation motion  Hydrogensulfide is a gas which turns filter paper soaked in aqueous lead(ethanoate from white to black. Hydrogen sulfide is slightly soluble in water. A long glass tube is set up as shown. long glass tube cotton wool soaked in aqueous hydrogen sulfide filter paper soaked in aqueous lead(ethanoate At first, the filter paper soaked in aqueous lead(ethanoate does not turn black. After a short time, the filter paper soaked in aqueous lead(ethanoate turns black. Explain these observations using the kinetic particle model. Sulfurdioxide is a pollutant in the air. Give one adverse effect of sulfurdioxide on buildings. Sulfurdioxide is used to bleach paper. Give one other use of sulfurdioxide. 
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
4. Electrochemistry  →  4.1. Electrolysis
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The structure of compoundA is shown. O O C C H H C H C O H H H H C H On the structure of compoundA, draw a circle around the carboxylicacid functional group.  State the name of the carboxylicacid that has only two carbon atoms. Deduce the molecular formula of compoundA to show the number of carbon, hydrogen and oxygen atoms. Explain, by referring to its structure, why compoundA is described as unsaturated. Ethene is an unsaturated hydrocarbon. Draw the structure of ethene to show all of the atoms and all of the bonds.  Ethene can be produced by cracking hydrocarbons. State the meaning of the term cracking. Give the conditions required for cracking.  Ethene can be polymerised. Complete these sentences about the polymerisation of ethene using words from the list. addition decomposition neutralisation polypolyreduction Terylene When ethene polymerises, it produces a molecule called . The type of reaction which occurs is .  Describe one pollution problem caused by non-biodegradable plastics. 
11. Organic chemistry  →  11.8. Polymers
11. Organic chemistry  →  11.2. Naming organic compounds
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Sodium is manufactured by electrolysis. Explain why sodium is manufactured by electrolysis and not by reduction with carbon. The diagram shows the equipment for the production of sodium. + – power supply sodium molten sodium chloride The anode is inert. Suggest a suitable substance that can be used for the anode. Label the anode on the diagram. Describe, by reference to the diagram, how you know that sodium is less dense than molten sodiumchloride. When concentrated aqueous sodium chloride is electrolysed, gases are produced at each electrode. State the names of the products and give the observations at each electrode. product at the negative electrode observations at the negative electrode product at the positive electrode observations at the positive electrode  Give two ways in which the physical properties of sodium are different from the physical properties of transition elements.  The symbol equation for the production of sodium hydride is shown. 2Na + H2 → 2NaH Write a word equation for this reaction. Suggest why the hydrogen must be dry. Sodiumhydride reduces iron(oxide to iron. Fe2O3 + 3NaH → 2Fe + 3NaOH Explain how this equation shows that iron(oxide is reduced. State the colour observed in the flame test for sodium. 
4. Electrochemistry  →  4.1. Electrolysis
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Aqueous ammonia is an alkali. Complete the dot-and-cross diagram to show the electron arrangement in a molecule of ammonia. H N H H  Complete the word equation for the reaction of aqueous ammonia with dilute hydrochloricacid. ammonia + hydrochloric acid  Describe the colour change when excess aqueous ammonia is added to an acidified solution of methylorange. from to ���������������������������������������������������������������� Aqueous ammonia reacts with aqueous copper(ions to produce compoundB. The formula of compoundB is CuN4H16O2. Complete the table to calculate the relative molecular mass of compoundB. type of atom number of atoms relative atomic mass copper 1 × 64 = 64 nitrogen 4 × 14 = 56 hydrogen oxygen  relative molecular mass =  Ammonia is used in the production of fertilisers. State why farmers put fertilisers on the soil where crops are to be grown. 
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
9. Metals  →  9.4. Reactivity series
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