Chemistry 0620/32 February/March 2024: question paper and mark scheme

Question

A list of substances is shown. brass calcium oxide carbon monoxide diamond glucose hydrogen litmus magnesium bromide methyl orange sodium chloride stainless steel thymolphthalein water zinc oxide Answer the following questions about these substances. Each substance may be used once, more than once or not at all. State which substance: (a) is formed by the thermal decomposition of calcium carbonate in the blast furnace . …… [1] (b) is a mixture of copper and zinc . …… [1] (c) turns yellow when an alkali is added . …… [1] (d) is a reactant in photosynthesis . …… [1] (e) is a salt that contains a positive ion with a charge of 1+ . …… [1] (f) is a compound that reduces iron(III) oxide in the blast furnace. . …… [1] [Total: 6]

Question

Table 2.1 shows the masses of some of the ions in a 1000 cm3 sample of river water. Table 2.1 mass of ion in 1000 cm3 name of ion formula of ion of river water / mg NH4+ 0.4 calcium Ca2+ 1.4 chloride Cl – 0.1 hydrogencarbonate HCO3– 1.2 magnesium Mg2+ 0.6 nitrate NO3– 0.8 phosphate PO43– 1.3 sodium Na+ 0.5 SO42– 0.4 (a) Answer these questions using the information in Table 2.1. (i) Name the negative ion that has the highest concentration. . …… [1] (ii) Name the compound that contains NH4+ and SO42– ions only. . …… [1] (iii) Calculate the mass of hydrogencarbonate ions in 200 cm3 of river water. mass = …… mg [1] (b) Give a test for sodium ions. test . …… observations …… [2] (c) Most of the nitrate ions in river water come from fertilisers used on fields. Describe the benefit of using fertilisers. . …… [1] (d) Water from natural sources can be polluted with harmful substances. State why sewage and phosphates in river water are harmful. sewage …… . …… phosphates …… . …… [2] (e) River water can contain acids such as ethanoic acid and methylbutanoic acid. (i) Draw the displayed formula for ethanoic acid. [1] (ii) Ethanoic acid reacts with sodium hydroxide. Complete the word equation for this reaction. ethanoic sodium …… …… + → + acid hydroxide [2] (iii) Methylbutanoic acid has the molecular formula C5H10O2. Complete Table 2.2 to calculate the relative molecular mass of C5H10O2. Table 2.2 relative atom number of atoms atomic mass carbon 5 12 5 × 12 = 60 hydrogen 1 oxygen 16 relative molecular mass = …… [2] [Total: 13]

Question

The chemical elements are arranged in the Periodic Table in groups and periods. (a) (i) Describe how the metallic character of the elements changes from left to right across a period. . …… . …… [1] (ii) The elements in Group I are known as the alkali metals. Describe two trends in the properties of the elements, going down Group I. 1 . …… 2 . …… [2] (b) Chlorine, bromine and iodine are in Group VII of the Periodic Table. (i) Aqueous chlorine reacts with aqueous sodium bromide to produce aqueous bromine and aqueous sodium chloride. Complete the symbol equation for this reaction. Cl 2 + ……NaBr → …… + 2NaCl[2] (ii) Suggest why aqueous iodine does not react with aqueous sodium bromide. . …… . …… [1] (iii) Complete the dot-and-cross diagram in Fig. 3.1 for a molecule of iodine. Show outer shell electrons only. I I Fig. 3.1 [2] (c) Molten silver bromide is electrolysed using graphite electrodes. Name the product formed at each electrode. product at the anode . …… product at the cathode . …… [2] (d) Fig. 3.2 shows the apparatus used to electroplate a metal object with silver. power supply + – electrolyte containing Ag+ ions Fig. 3.2 (i) Label Fig. 3.2 to show where the silver is deposited. [1] (ii) State why objects are electroplated. . …… [1] [Total: 12]

Question

Alkenes are a homologous series of hydrocarbons which are made by cracking larger alkane molecules. (a) (i) Write the general formula for alkenes. . …… [1] (ii) Explain the need for cracking larger alkane molecules. . …… . …… [1] (iii) Describe two conditions needed for cracking. 1 . …… 2 . …… [2] (b) Alkenes are unsaturated compounds. State the meaning of the term unsaturated. . …… . …… [1] (c) Table 4.1 shows the boiling points of some alkenes. Table 4.1 boiling point alkene / °C ethene –104 propene butene –6 pentene 30 hexene 63 (i) Predict the boiling point of propene. . …… °C [1] (ii) The melting point of butene is –185 °C. Deduce the physical state of butene at –100 °C. Give a reason for your answer. physical state . …… reason . …… . …… [2] (d) Fig. 4.1 shows a gas syringe that contains 60 cm3 of ethene gas. end of gas syringe blocked ethene gas Fig. 4.1 State how the volume of ethene in the gas syringe changes when the temperature is decreased and the pressure remains the same. . …… [1] (e) Poly(ethene) is produced by the polymerisation of ethene. The reaction is exothermic. (i) State the meaning of the term exothermic. . …… [1] (ii) Fig. 4.2 shows the reaction pathway diagram for this reaction. ethene energy poly(ethene) progress of reaction Fig. 4.2 Explain how this reaction pathway diagram shows that the reaction is exothermic. . …… . …… [1] (f) Ethene reacts with steam to produce ethanol. (i) Complete the symbol equation for this reaction. C2H4 + …… → …… [2] (ii) Choose the word which describes the type of catalyst used in this reaction. Draw a circle around your chosen answer. acid alkali metal salt[1] [Total: 14] Question 5 starts on the next page.

Question

Samarium is a metal. (a) Deduce the number of electrons and neutrons in the samarium atom shown. 62Sm 154 number of electrons . …… number of neutrons …… [2] (b) Samarium has properties that are similar to the properties of transition elements. Choose one statement about samarium that is correct. Tick (✓) one box. Compounds of samarium are colourless. Samarium has a low melting point. Samarium and its compounds do not act as catalysts. Samarium has a high density. [1] (c) Large pieces of samarium react with cold water to produce hydrogen gas. 2Sm + 6H2O → 2Sm(OH)3 + 3H2 (i) Complete Fig. 5.1 by drawing the apparatus to show how the volume of hydrogen gas is measured during this reaction. cold water large pieces of samarium Fig. 5.1 [2] (ii) The experiment is repeated using hot water instead of cold water. All other conditions stay the same. Describe how the rate of reaction changes when hot water is used. . …… [1] (iii) The experiment is repeated using powdered samarium instead of large pieces of samarium. All other conditions stay the same. Describe how the rate of reaction changes when powdered samarium is used. . …… [1] (d) Table 5.1 shows the observations when samarium and three other metals are heated in oxygen. Table 5.1 metal observations nickel reacts very slowly samarium reacts rapidly strontium reacts very rapidly yttrium does not react Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive [2] (e) Samarium reacts with oxygen to produce samarium oxide, Sm2O3. Complete the symbol equation for this reaction. ……Sm + 3O2 → ……Sm2O3[2] (f) Hydrated samarium chloride is an ionic compound. (i) Define the term hydrated. . …… . …… [1] (ii) State two physical properties of an ionic compound. 1 . …… 2 . …… [2] [Total: 14] Question 6 starts on the next page.

Question

Sulfur is an element in Group VI of the Periodic Table. (a) State the meaning of the term element. . …… . …… [1] (b) Sulfur has a relative atomic mass of 32. Complete these sentences about the relative atomic mass of sulfur using terms from the list. 12 C electrons 1 H isotopes neutrons 16 O protons 32 S The relative atomic mass of sulfur is the average mass of the sulfur …… . This average mass is compared to 1/12th of the mass of an atom of …… . [2] (c) Sulfur is a solid at room temperature and pressure. Describe the motion and separation of the particles in solid sulfur. motion . …… . …… separation . …… . …… [2] (d) Liquid sulfur reacts with chlorine to produce disulfur dichloride. 2S + Cl 2 → S2Cl 2 (i) Describe how the general physical properties of a liquid differ from those of a solid. Give two differences. 1 . …… 2 . …… [2] (ii) When 6.4 g of sulfur reacts with excess chlorine, 13.5 g of disulfur dichloride is produced. Calculate the mass of disulfur dichloride produced when 19.2 g of sulfur reacts with excess chlorine. mass = …… g [1] (e) Sulfur dioxide is formed when sulfur burns in air. (i) State the percentage of oxygen in clean, dry air. . …… [1] (ii) State one source of the pollutant sulfur dioxide in the air other than from burning sulfur. . …… [1] (iii) State one adverse effect of sulfur dioxide in the air. . …… [1] (iv) State one method of reducing the emissions of sulfur dioxide. . …… [1] (v) Sulfur dioxide dissolves in water to form sulfurous acid. Give the formula of the ion that is present in all aqueous acids. . …… [1] (vi) Sulfur dioxide reacts with oxygen in the presence of a catalyst to form sulfur trioxide. This is a reversible reaction. Complete the equation for this reaction by writing the sign for a reversible reaction in the box. 2SO2 + O2 2SO3[1] [Total: 14]

Question

Magnesium is an element in Group II of the Periodic Table. (a) Deduce the electronic configuration of magnesium. . …… [1] (b) Magnesium can be produced by reducing magnesium oxide with barium. MgO + Ba → Mg + BaO Explain how this equation shows that magnesium oxide is reduced. . …… [1] (c) Alloys of magnesium and aluminium are resistant to corrosion. Choose the diagram, A, B, C or D, in Fig. 7.1 that best shows the structure of an alloy. A B C D Fig. 7.1 diagram . …… [1] (d) (i) Complete the word equation for the reaction of magnesium oxide with hydrochloric acid. magnesium hydrochloric …… …… + → + oxide acid [2] (ii) Magnesium oxide is insoluble in water. Choose from the list one other compound that is insoluble in water. Tick (✓) one box. magnesium carbonate magnesium chloride magnesium nitrate magnesium sulfate [1] (e) Fig. 7.2 shows the electronic configuration of an element in Group II of the Periodic Table. Fig. 7.2 Deduce the period in the Periodic Table to which this element belongs. Period …… [1] [Total: 7] The Periodic Table of Elements Group I II III IV V VI VII VIII 1 2 H He hydrogen helium Key 1 4 3 4 atomic number 5 6 7 8 9 10 Li Be atomic symbol B C N O F Ne lithium beryllium name boron carbon nitrogen oxygen fluorine neon 7 9 relative atomic mass 11 12 14 16 19 20 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar sodium magnesium aluminium silicon phosphorus sulfur chlorine argon 23 24 27 28 31 32 35.5 40 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton 39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 20 rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon 85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131 55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 lanthanoids Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn caesium barium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth polonium astatine radon 133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – – 87 88 89–103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 actinoids Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson – – – – – – – – – – – – – – – – – 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 lanthanoids La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium 139 140 141 144 – 150 152 157 159 163 165 167 169 173 175 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 actinoids Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium – 232 231 238 – – – – – – – – – – – The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).