Chemistry 0620/42 February/March 2019: question paper and mark scheme

Question

Period 3 of the Periodic Table is shown. sodium magnesium aluminium silicon phosphorus sulfur chlorine argon Answer the following questions using only these elements. Each element may be used once, more than once or not at all. State which element: (a) is a gas at room temperature and pressure . …… [1] (b) forms a basic oxide with a formula of the form X2O . …… [1] (c) is made of atoms which have a full outer shell of electrons . …… [1] (d) forms an oxide which causes acid rain . …… [1] (e) is extracted from bauxite . …… [1] (f) forms an oxide which has a macromolecular structure . …… [1] (g) consists of diatomic molecules. . …… [1] [Total: 7]

Question

(a) The table gives information about some atoms or ions, A, B and C. Complete the table. number of number of electronic charge protons electrons structure A 11 10 2,8 B 18 0 C 10 2,8 –1 [4] (b) (i) Carbon is an element. Define the term element. . …… . …… [1] 6C, 6C and 6C are isotopes of carbon. 12 13 14 (ii) Complete the table. number of protons number of neutrons 6C 12 6C 13 6C 14 [2] [Total: 7]

Question

Fluorine is a Group VII element. Fluorine forms compounds with metals and non-metals. (a) Predict the physical state of fluorine at room temperature and pressure. . …… [1] (b) Fluorine exists as diatomic molecules. Complete the dot-and-cross diagram to show the electron arrangement in a molecule of fluorine. Show outer shell electrons only. F F [2] (c) Write a chemical equation for the reaction between sodium and fluorine. . …… [2] (d) Explain why chlorine does not react with aqueous sodium fluoride. . …… . …… [1] (e) Tetrafluoromethane and lead(II) fluoride are fluorides of Group IV elements. Some properties of tetrafluoromethane and lead(II) fluoride are shown in the table. property tetrafluoromethane lead(II) fluoride formula CF4 melting point / °C –184 855 boiling point / °C –127 1290 conduction of electricity when solid non-conductor non-conductor conduction of electricity when molten non-conductor good conductor (i) What is the formula of lead(II) fluoride? . …… [1] (ii) What type of bonding is present between the atoms in tetrafluoromethane? . …… [1] (iii) What type of structure does solid lead(II) fluoride have? . …… [1] (iv) Explain, in terms of attractive forces between particles, why lead(II) fluoride has a much higher melting point than tetrafluoromethane. In your answer refer to the types of attractive forces between particles and their relative strengths. . …… . …… . …… . …… [3] (f) Tetrafluoroethene is an unsaturated compound with the formula C2F4. Tetrafluoroethene is the monomer used to make the polymer poly(tetrafluoroethene). (i) What is meant by the term unsaturated ? . …… . …… [1] (ii) Describe a test to show that tetrafluoroethene is unsaturated. test. …… observations…… [2] (iii) Draw the structure of a molecule of tetrafluoroethene. Show all of the atoms and all of the bonds. [1] (iv) Tetrafluoroethene can be polymerised to form poly(tetrafluoroethene). Draw one repeat unit of poly(tetrafluoroethene). Show all of the atoms and all of the bonds. [2] (v) Deduce the empirical formula of: tetrafluoroethene …… poly(tetrafluoroethene). …… [2] [Total: 20]

Question

This question is about ethanoic acid, CH3COOH. (a) Ethanoic acid is manufactured from methanol and carbon monoxide. CH3OH(g) + CO(g) CH3COOH(g) The process is done at 200 °C and 30 atmospheres pressure. The forward reaction is exothermic. Complete the table using only the words increases, decreases or no change. effect on the rate of effect on the equilibrium the forward reaction yield of CH3COOH(g) adding a catalyst no change increasing the temperature decreasing the pressure decreases [4] (b) How would you show that an aqueous solution of ethanoic acid is an acid without using an indicator or measuring the pH? State the reagent you would use and give the expected observations. Write a chemical equation for the reaction that you describe. ●● reagent . …… ●● expected observations . …… . …… ●● chemical equation . …… [3] (c) Ethanoic acid is a weak acid. (i) What is meant by the term acid ? . …… . …… [1] (ii) Why is ethanoic acid described as weak ? . …… . …… [1] (d) Ethanoic acid reacts with methanol to form an ester. (i) State two conditions required for this reaction. 1 . …… 2 . …… [2] (ii) Draw the structure of the ester formed when ethanoic acid reacts with methanol. Show all of the atoms and all of the bonds. Name the ester. structure name . …… [3] (iii) Name an ester which is a structural isomer of the ester in (d)(ii). . …… [1] [Total: 15]

Question

Titanium is extracted from an ore called rutile. Rutile is an impure form of titanium(IV) oxide, TiO2. (a) Rutile is mixed with coke and heated in a furnace through which chlorine gas is passed. The product is gaseous titanium(IV) chloride, TiCl 4. TiO2(s) + 2C(s) + 2Cl 2(g) TiCl 4(g) + 2CO(g) The gaseous titanium(IV) chloride produced is condensed into the liquid state. The titanium(IV) chloride is then separated from liquid impurities. (i) Suggest the name of the process by which liquid titanium(IV) chloride could be separated from the liquid impurities. . …… [1] (ii) Carbon monoxide, CO(g), is also produced in the reaction. Why should carbon monoxide not be released into the atmosphere? . …… [1] (b) Calculate the volume of chlorine gas, Cl 2(g), at room temperature and pressure, that reacts completely with 400 g of TiO2(s) using the following steps. TiO2(s) + 2Cl 2(g) + 2C(s) TiCl 4(g) + 2CO(g) ●● Calculate the relative formula mass, Mr, of TiO2. Mr of TiO2 = …… ●● Calculate the number of moles in 400 g of TiO2. …… mol ●● Determine the number of moles of Cl 2 that react with 400 g of TiO2. moles of Cl 2 = …… mol ●● Calculate the volume of Cl 2 that reacts with 400 g of TiO2. volume of Cl 2 = …… dm3 [4] (c) Titanium(IV) chloride, TiCl 4, is heated with an excess of magnesium, in an atmosphere of argon. (i) Balance the chemical equation for the reaction. TiCl 4 + …… Mg Ti + …… MgCl 2 [1] (ii) Titanium(IV) chloride can be reacted with sodium instead of magnesium. The reaction between titanium(IV) chloride and sodium is similar to the reaction between titanium(IV) chloride and magnesium. Write a chemical equation for the reaction between titanium(IV) chloride and sodium. . …… [1] (iii) Suggest why the reaction between titanium(IV) chloride and magnesium is done in an atmosphere of argon and not in air. . …… . …… [1] (d) After titanium(IV) chloride is heated with magnesium, the unreacted magnesium is removed by adding an excess of dilute hydrochloric acid to the mixture. The dilute hydrochloric acid also dissolves the magnesium chloride. The dilute hydrochloric acid does not react with the titanium or dissolve it. (i) Give two observations and write a chemical equation for the reaction that occurs when dilute hydrochloric acid reacts with magnesium. 1 . …… 2 . …… chemical equation . …… [3] (ii) Name the process that is used to separate the titanium from the mixture after all the magnesium has been removed. . …… [1] (iii) Titanium does not react with the dilute hydrochloric acid or dissolve in it. Suggest why titanium does not react with dilute hydrochloric acid. . …… [1] (e) Magnesium cannot be produced by electrolysis of aqueous magnesium chloride using inert electrodes. (i) Name the product formed at the negative electrode (cathode) during the electrolysis of aqueous magnesium chloride. . …… [1] (ii) Suggest how magnesium can be produced from magnesium chloride by electrolysis. . …… [1] [Total: 16]

Question

This question is about transition elements. (a) Transition elements are harder and stronger than Group I elements. Describe two other differences in physical properties between transition elements and Group I elements. 1 . …… 2 . …… [2] (b) State one physical property of transition elements that is similar to Group I elements. . …… [1] (c) State two chemical properties of transition elements. 1 . …… 2 . …… [2] (d) Cobalt is a transition element. Anhydrous cobalt(II) chloride is used to test for water. State the colour change that occurs when water is added to anhydrous cobalt(II) chloride. from …… to …… [2] (e) Iron is a transition element. (i) Which two substances react with iron to form rust? 1 . …… 2 . …… [2] (ii) Which metal is used to galvanise iron? . …… [1] (f) The hull of a ship is made from steel (mainly iron). Metal blocks are placed on the ship’s hull to prevent rusting. water water ship’s hull metal block Use your knowledge of the reactivity series to explain why: ●● magnesium is suitable to use as the metal blocks ●● c opper is not suitable to use as the metal blocks. . …… . …… . …… [2] (g) Rust contains iron(III) oxide. Phosphoric acid, H3PO4, can be used to remove rust from an iron object and prevent further rusting. (i) Write a chemical equation for the reaction between iron(III) oxide and phosphoric acid to form iron(III) phosphate and water. . …… [2] (ii) Iron(III) phosphate is an insoluble salt. Suggest how the formation of iron(III) phosphate prevents further rusting. . …… . …… [1] [Total: 15] 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.).