Chemistry 0620/42 May/June 2022: question paper and mark scheme

Question

The symbols of the elements of Period 3 of the Periodic Table are shown. Na Mg Al Si P S Cl Ar Answer the following questions about these elements. Each symbol may be used once, more than once or not at all. Write the symbol of the element which: [Total: 8] Question 2 starts on the next page.

Question

Calcium hydroxide, Ca(OH)2, is slightly soluble in water. (a) Calcium hydroxide can be made by the reaction of calcium with water. (i) Write the chemical equation for this reaction. . …… [2] (ii) Name another substance that reacts with water to form calcium hydroxide. . …… [1] (b) When calcium hydroxide dissolves in water, it dissociates into ions and forms a weakly alkaline solution. (i) Suggest the pH of aqueous calcium hydroxide. . …… [1] (ii) Give the formula of the ion responsible for making the solution alkaline. . …… [1] (c) Limewater is a saturated solution of calcium hydroxide, Ca(OH)2(aq). (i) Name the gas limewater is used to test for. . …… [1] (ii) Suggest what is meant by the term saturated solution. . …… . …… [2] (iii) Describe how you would make a sample of limewater starting with solid calcium hydroxide. . …… . …… . …… [2] (iv) Describe how you would test for the presence of calcium ions in a sample of limewater. test . …… observations …… . …… [3] (d) A 25.0 cm3 sample of limewater is placed in a conical flask. The concentration of Ca(OH)2 in the limewater is determined by titration with dilute hydrochloric acid, HCl. (i) Name the item of apparatus used to measure the volume of acid in this titration. . …… [1] (ii) State the type of reaction which takes place. . …… [1] (iii) As well as limewater and dilute hydrochloric acid, state what other type of substance must be added to the conical flask. . …… [1] (iv) The equation for the reaction is shown. Ca(OH)2 + 2HCl → CaCl 2 + 2H2O 20.0 cm3 of 0.0500 mol / dm3 HCl reacts with the 25.0 cm3 of Ca(OH)2. Determine the concentration of Ca(OH)2 in g / dm3. Use the following steps. ● Calculate the number of moles in 20.0 cm3 of 0.0500 mol / dm3 HCl. …… mol ● Determine the number of moles of Ca(OH)2 in 25.0 cm3 of the limewater. …… mol ● Calculate the concentration of Ca(OH)2 in mol / dm3. …… mol / dm3 ● Determine the concentration of Ca(OH)2 in g / dm3. …… g / dm3 [5] [Total: 21]

Question

Transition elements are found in the middle block of the Periodic Table. (a) Chromium has several isotopes. Manganese has only one isotope. (i) State what is meant by the term isotopes. . …… . …… [2] (ii) State the nucleon number of manganese. . …… [1] (iii) Complete the table to show the number of protons, neutrons and electrons in a 24 52 Cr3+ ion. protons neutrons electrons [3] (b) One chemical property of transition elements is that they form coloured compounds. (i) Give the colours of the following hydrated salts. [2] (ii) State two other chemical properties of transition elements. 1 . …… 2 . …… [2] (c) Transition elements and Group I elements are metals. They share many physical properties including the ability to: ● conduct electricity ● be hammered into shape. (i) Explain why transition elements and Group I elements conduct electricity. . …… [1] (ii) State the property that describes a material which can be hammered into shape. . …… [1] (d) Transition elements and Group I elements differ in other physical properties. Transition elements are harder and stronger than Group I elements. Describe two other ways in which the physical properties of transition elements differ from Group I elements. 1 . …… 2 . …… [2] [Total: 14]

Question

Fluorine and chlorine are halogens. (a) Suggest the appearance of fluorine. . …… [1] (b) Fluorine reacts with sulfur to form a compound which has 25.2% sulfur by mass and a relative molecular mass of 254. Determine the molecular formula of this compound. molecular formula = …… [3] (c) Nitrogen trichloride, NCl 3, is a covalent compound. Complete the dot-and-cross diagram to show the electron arrangement in a molecule of NCl 3. Show outer electrons only. Cl N Cl Cl [3] (d) Lithium chloride, LiCl, is an ionic compound. Complete the dot-and-cross diagram to show the electron arrangement and charges of the ions in lithium chloride. Li Cl [3] (e) Explain, in terms of attractive forces between particles, why LiCl is a solid at room temperature but NCl 3 is a liquid with a relatively low boiling point. . …… . …… . …… [3] [Total: 13]

Question

The reaction scheme shows five organic reactions, numbered 1 to 5. carbon dioxide + water 2 1 3 4 sugar ethanol alkene A alkane B 5 compound C (a) Name reaction 1. . …… [1] (b) Name reaction 2 and write the chemical equation for this reaction. name . …… equation . …… [3] (c) Reaction 3 forms ethanol from alkene A. (i) Identify alkene A. . …… [1] (ii) State the type of reaction that occurs during reaction 3. . …… [1] (iii) State the reagents and conditions needed for reaction 3. . …… . …… [2] (d) Alkene A is converted into alkane B in reaction 4. (i) State the reagent and conditions for reaction 4. . …… . …… [3] (ii) State the general formula of alkanes. . …… [1] (e) Ethanol is oxidised in reaction 5 by heating it with dilute sulfuric acid and one other reagent. (i) Identify the other reagent in reaction 5. . …… [1] (ii) Name the homologous series compound C belongs to. . …… [1] (iii) Draw the structure of compound C. Show all of the atoms and all of the bonds. [1] [Total: 15]

Question

This question is about polymers. (a) Polymer X is a condensation polymer. Part of the structure of polymer X is shown. O O O C O O C C O (i) How many molecules of water are produced when this part of polymer X is formed from its monomers? . …… [1] (ii) Complete the structures of the two monomers used to make polymer X. Show all of the atoms and all of the bonds in the functional groups. and [2] (iii) What type of condensation polymer is X? . …… [1] (b) Part of polymer Y has the structure shown. O O O C O C O C O State the number of different types of monomer needed to make polymer Y. . …… [1] (c) Part of polymer Z has the structure shown. CH3 H CH3 H CH3 H C C C C C C H CH3 H CH3 H CH3 (i) Draw and name the structure of the monomer which forms polymer Z. Show all of the atoms and all of the bonds. name …… [3] (ii) Name the chemical process used to make the monomer that forms polymer Z. . …… [1] [Total: 9] 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 rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon 16 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 89–103 104 105 106 107 108 109 110 111 112 114 116 actinoids Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Fl Lv francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium flerovium livermorium – – – – – – – – – – – – – 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.).