Physical Sciences Grade 12 P2 North West Mock 2018 QP

Downloaded from hlayiso.com Education and Sport Development Department of Education and Sport Development Departement van Onderwys en Sporto ntwikkeling Lefapha la Thuto le Tlhabololo ya Metshameko NORTH WEST PROVINCE NATIONAL SENIOR CERTIFICATE i PHYSICAL SCIENCES: CHEMISTRY (P2) i i SEPTEMBER 2018 | ee ee ees MARKS: 150 TIME: 3 hours This question paper consists of 14 pages and 4 data sheets. Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 3 NW/September 2018 NSC QUESTION 1: MULTIPLE-CHOICE QUESTIONS Various options are provided as possible answers to the following questions. Choose the answer and write only the letter (A-D) next to the question number (1.1—1.10) in the ANSWER BOOK, for example 1.11 D. 1.1. Which ONE of the following is the general formula of alkenes? A B c D ConHen CaHen-n CaHens2 CaHon (2) 1.2. Which ONE of the following isomers has the LOWEST boiling point? A B Cc D CH3CH2CH2CH2CH2CHs CH3CH(CH3)CH2CH2CH3 CH3CH2C(CH3)2CHs CH3CH2CH(CH3)CH2CH3 (2) 1.3 The structural formula of an organic compound is shown below: —_ LO —_ H ; H—C-H c C iO | | | H =I— O— ps a a = | H 4 H Which ONE of the following is the correct IUPAC name of this compound? A B Cc D 4-methyl-5-ethylhex-3-ene 4,5-dimethylhept-3-ene 3,4-dimethylhept-4-ene 3-methyl-4-ethylhept-4-ene @) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 4 NW/September 2018 NSC 1.4. Which ONE of the following statements about neutralisation is CORRECT? Neutralisation is ... A a reaction in which water reacts with itself to form ions. B a process in which ionic compounds split into ions. Cc the reaction of an acid with a base to form salt and water. D a solution of a known concentration. (2) 1.5. The sketch graph below represents the change in potential energy for an hypothetical chemical reaction’ K ——> L L Vv Course of reaction AH for the forward reaction is given by: A B-C B C-D Cc D-B D D-C (2) 1.6 Initially 2 mol CO(g) and 2 mol H2(g) are sealed in a container. The reaction reaches equilibruim according to the following balanced equation: CO(g) + 2H2(g) = CHsOH(g) At equilibruim the amount of CHsOH(g) in the mixture will be ... A 1 mol. B 2 mol. Cc less than 1 mol. D greater than 1 mol. (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 5 NW/September 2018 NSC 1.7 Which ONE of the following metals will react MORE spontaneously than the other with hydrochloric acid? A Cu B Ag Cc Pt D Mg (2) 1.8 Given the following solutions: e@ Solution A: pH of 10 e Solution B: pH of 7 e® Solution C: pH of 5 Arrange the above solutions in order of increasing H* concentration? A A,B,C B B, A, C C CAB D C,B,A (2) 1.9 Asmall piece of Mg is added to 5 cm’ of a dilute hydrochloric acid solution in a test tube. Which ONE of the following changes will affect the rate at which hydrogen gas is produced in this reaction? A Using 10 cm? of the same dilute hydrochloric solution B Increasing the concentration of the hydrochloric solution (e Decreasing the concentration of the hydrochloric solution D Decreasing the temperature of the hydrochloric solution (2) 1.10 A gardener needs a fertiliser with the highest percentage of the relevant nutrient to obtain quality flowers and fruit. Which ONE of the following NPK fertilisers will produce the best results? A 23795 B 1:507¢ Cc 2:3:4 D 1: 515 3 (2) [20] Copyright reserved Please turn over

Physical Sciences/P2 6 NW/September 2018 Downloaded from hlayiso.com NSC QUESTION 2 (Start on a new page.) Study the organic compounds represented by the letters A to F below and answer the questions that follows. 2.4 2.2 2.3 2.4 Copyright reserved A B Catto | CHsCHzCH2CH,COOH c D CH3CH2,CHCH2 CH3CH2CH2CH2CH3 E F CH: CsHi2 ee CHs CH3 Define the term chain isomer. (2) Write down: 2.2.1. The letters of TWO compounds that are chain isomers of compound E. (2) 2.2.2 The IUPAC name of compound F. (2) ° Jane adds a few drops of bromine water (Br2) to compounds C and D in separate test tubes in a dark room. She observes that one compound decolourises the bromine water immediately, whilst the other one only reacts after placing the test tube in direct sunlight. Write down the following: 2.3.1 What is the purpose of this test in a laboratory? (1) 2.3.2 Name the type of reaction that takes place in the test tube containing compound C. (1) 2.3.3 Give the letter of the compound that decolourises the bromine water spontaneously. Explain your answer. (2) Write down the structural formula and the IUPAC name of the ester formed when methanol reacts with compound B. (4) [14] Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 7 NW/Sepitember 2018 NSC QUESTION 3 (Start on a new page.) Learners investigate the factors which influence the boiling points of alcohols. They use equal volumes of each of the alcohols and heat them separately in a water bath. The temperature at which each type of alcohol boils, is measured. The results obtained, are shown in the table below: ALCOHOL BOILING POINTS OF ALCOHOL (°C) Butan-1-ol 117,7 Pentan-1-ol 138,5 Hexan-1-ol 157,0 3.1. Define the term vapour pressure. (2) 3.2. Which ONE of the alcohols above will have the highest vapour pressure? (1) 3.3. The boiling points of the alcohols are compared with each other. 3.3.1 What structural requirements must the alcohols meet to make it a fair comparison? (2) 3.3.2 Fully explain the trend in the boiling points. (3) 3.4. How will the boiling point of pentan-1-ol be affected if the volume of pentan-1-ol used, is halved? Choose from INCREASES, DECREASES or REMAINS THE SAME. (1) 3.5 During a combustion reaction in a closed container of adjustable volume, 10 cm? of compound butane reacts in excess oxygen according to the following balanced equation: 2CaHi0(g) + 130g) — 8COz(g) + 10H20(g) The initial volume of oxygen in the container is given as 70 cm’. (Assume that ALL the gases in the container are at the same temperature and pressure.) Calculate the TOTAL volume of the gases that are present in the container by the end of the reaction. (5) [14] Copyright reserved Please turn over

Physical Sciences/P2 NSC QUESTION 4 (Start on a new page.) The flow diagram below shows how an alkane can be used to prepare other organic compounds. The letters A to G represent different organic reactions. 41 4.2 4.3 4.4 4.5 Compound X G Downloaded from hlayiso.com NW/September 2018 Ce, Hce B H H Propane FL oan | *——_| An alcohol # ¢ ii H Cc HO (major product) H H wal E HBr —— Compound Y (major product) Write down the type of reactions represented by: 4.1.1 F 41.2 G 413 B Write down the IUPAC name of compound Y. For reaction E, write down: (1) (1) (1) (2) 4.3.1 The type of elimination reaction (1) 4.3.2 TWO reaction conditions (2) Write down the: 4.4.1. FORMULA of an inorganic reactant needed for reaction C (1) 4.4.2. Balanced chemical equation for reaction A, using STRUCTURAL FORMULAE (4) There are natural polymers and man-made polymers like plastics. Polythene is a plastic polymer that is widely used. 4.5.1 Describe addition polymerisation. 4.5.2 Write down ONE use of polythene. Copyright reserved (2) (1) [16] Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 9 NSC QUESTION 5 (Start on a new page.) A Grade 12 learner investigates the effect of surface area of a solid reactant on the rate of a chemical reaction. The investigation was done by adding 1,5 g of CaCO3 to excess hydrochloric acid. The balanced chemical equation for the reaction is: CaCO,(s) + 2HCf(aq) - CaCt(aq) + CO2(g) + H2O(2) 5.1. Define the term rate of reaction. (2) 5.2 In this investigation, write down the dependent variable. (1) 5.3 In which state of division of the CaCO; (lumps or powder) will it take a shorter time for the reaction to reach completion? Explain your answer. (3) 5.4 Assume that all CaCO3 reacted and calculate the mass of carbon dioxide NW/September 2018 formed during the reaction. (4) Mass of | State of Concentration of | Temperature CaCO,(s) | CaCO,(s) HCE (mol.dm*) of HC (°C) Experiment 1 2 Lumps 0,5 30 Experiment 2 2 Powder 0,5 30 Experiment 3 2 Powder 0,5 30 5.5 The learners repeat the investigation above, but now the temperature of the HCt is increased from 30 °C to 40 °C in Experiment 1. 5.5.1 How will the change in temperature affects the rate of the reaction? (2) 5.5.2 Use the collision theory to explain the observation in QUESTION 5.5.1. (3) [15] Copyright reserved

Downloaded from hlayiso.com Physical Sciences/P2 10 NW/September 2018 NSC QUESTION 6 (Start on a new page.) Gases X and Y are pumped into a 2 dm® container. When the container is sealed, 4 moles of gas X and 4 moles of gas Y are present. The following equilibrium is reached at a certain temperature (400 °C): 2X(g) + 3Y(g) = X2Ya(g) The graph below shows the number of moles of gases X, Y and X2Y3 present in the container at different times. A 4 1) = i ° H & t £ ' { ‘ = ' 3 ' , : fe) j } H E | as 1X2Ya(g) | ' 0,6) 30 70 100 Time (s) 6.1. How many moles of gas X2Y3 are formed by the time the reaction reaches equilibrium after 30 seconds? (1) 6.2 Calculate the value of the equilibrium constant at t = 30 s. (7) 6.3 Att= 70s, the temperature is increased. Is the forward reaction ENDOTHERMIC or EXOTHERMIC? Explain your answer in terms of Le Chatelier’s principle. (3) 6.4 How will this increase in temperature affect the value of the equilibrium constant? Choose from INCREASE, DECREASE or NO EFFECT. (1) [12] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 A NW/September 2018 NSC QUESTION 7 (Start on a new page.) The Arrhenius and Lowry-Brensted theories can be used to define an acid or a base. 7.1. 2 7.3 Define the term acid according to the Arrhenius theory. (2) Consider the following chemical reactions: P: SQ,+H,O = 2H*+SO> Q: HCl(ag) + NHa(g) = NH (aq) + Cf(aq) 7.2.1. From reactions P and Q, identify the reaction that illustrates the Arrhenius theory. (1) 7.2.2 The ammonium ions (NH,") in chemical reaction Q undergoes hydrolysis. (a) | Write down a balanced chemical equation for the hydrolysis of the ammonium ions. (3) (b) Will the resultant solution be ACIDIC, BASIC or NEUTRAL? Explain your answer by referring to QUESTION 7.2.2(a) above. (2) A sodium hydroxide solution (NaOH) is prepared by dissolving 4 g of sodium hydroxide in water to make a 500 cm? solution. 7.3.1 Calculate the concentration of the sodium hydroxide solution. (3) During a titration, 12,5 cm? of a sodium hydroxide (NaOH) solution neutralises 25 cm? of a sulphuric acid (H2SO,) solution, according to the following balanced chemical equation: 2NaOH(aq) + H2SO,(aq) > NazSOu(ag) + 2H20(2) 7.3.2 Calculate the pH of the H2SO, solution. (7) [18] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 12 NW/September 2018 NSC QUESTION 8 (Start on a new page.) The following THREE unknown half-cell reactions under standard conditions are given in the table below. Metal X displaces Y”" ions in a YSO,(aq) solution and metal Z displaces X** ions in a XSO,(aq) solution. NUMBER HALF-CELL ELECTROLYTE 1 xIX*(aq) X80, (aq) 2 YIY"*(aq) YSO.(aq) 3 ZIZ"*(aq) ZSO,(aq) Use the information above to answer the following questions: 8.1 Define the term electrolyte. (2) 8.2 Write down TWO conditions needed for these half-cell reactions to function under standard conditions. (2) 8.3 When metal X displaces Y** ions ina YSO, solution, will Y°* be oxidised or reduced? Give a reason for your answer. (2) 8.4 Arrange metals X, Y and Z in order of increasing reducing ability. (1) 8.5 Suppose metals Mg, Cu and Ni replace metals X, Y and Z and are now used to set up a galvanic cell under standard conditions. 8.5.1 Referring to the standard reduction potentials table, use calculations to identify (from the metals above) a suitable pair of electrodes that will produce an emf of 2,7 V. (4) 8.5.2 Write down the cell notation of the cell in QUESTION 8.5.1 above. (3) 8.5.3 Is this cell reaction EXOTHERMIC or ENDOTHERMIC? (1) [15] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 13 NW/September 2018 NSC QUESTION 9 (Start on a new page.) The sketch below shows a cell used in the purification of copper. Study the sketch below and then answer the given questions. battery CuCe,(aq) 9.1 State the type of energy conversion taking place when the above cell is in operation. (2) 9.2 Which of these electrodes (P or Q) is the impure copper? (1) 9.3. Which electrode will show an increase in mass? (1) 9.4 Write down the equation of the half-cell reaction that takes place at the anode. (2) 9.5 Explain why the colour of the copper ions solution remains unchanged. (2) The electrodes are now replaced with carbon rods. 9.6 Atwhich electrode will chlorine gas be formed (P or Q)? Use a chemical equation (half-reaction) to show the formation of chlorine gas. (3) 9.7. When carbon rods are being used, state whether the concentration of the electrolyte INCREASES, DECREASES or REMAINS THE SAME. (1) [12] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 14 NW/September 2018 NSC QUESTION 10 (Start on a new page.) Different types of fertilisers can be prepared directly from ammonia, nitric acid or sulphuric acid. Reactions K, L, M and N in the flow diagram below represent the manufacturing of fertiliser X. H2,O | N 10.1 Write down the NAME of the process during which sulphuric acid is prepared. (1) 10.2 Write down: 10.2.1 A balanced chemical equation for reaction K (3) 10.2.2 The NAME or FORMULA of the catalyst used in reaction K (2) 10.3 In the following reaction the fertiliser ammonium sulphate could be prepared as follows: sulphuric acid +Z —- ammonium sulphate Write down: 10.3.1 The name of reactant Z (1) 10.3.2. A balanced chemical equation for the reaction above (3) 10.4 Calculate the percentage of nitrogen in ammonium sulphate. (4) [14] TOTAL: 150 Copyright reserved Please turn over