Physical Sciences Grade 12 Free State Mock 2020 Question Paper

Copy right reserved education Department of Education FREE STATE PROVINCE PREPARATORY EXAMINATION GRADE 12 PHYSICAL SCIENCES P2 (CHEMISTRY) SEPTEMBER 2020 MARKS: 150 TIME: 3 HOURS This question paper consists of 16 pages and 4 data sheets. nA Please turn over

Downloaded from hlayiso.com Physical Sciences P2 2 FS/September 2020 Grade 12 Prep. Exam. INSTRUCTIONS AND INFORMATION A 10. 11. 12. Write your name and other applicable information in the appropriate spaces on the ANSWER BOOK. The question paper consists of EIGHT questions. Answer ALL the questions in the ANSWER BOOK. Start EACH question on a NEW page in the ANSWER BOOK. Number the answers correctly according to the numbering system used in this question paper. Leave ONE line between two subquestions, for example between QUESTION 2.1 and QUESTION 2.2. You may use a non-programmable pocket calculator. You may use appropriate mathematical instruments. You are advised to use the attached DATA SHEETS. Show ALL formulae and substitutions in ALL calculations. Round off your FINAL numerical answers to a minimum of TWO decimal places where necessary. Give brief motivations, discussions, et cetera where required. Write neatly and legibly. Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 3 FS/September 2020 Grade 12 Prep. Exam. QUESTION 1: MULTIPLE-CHOICE QUESTIONS Four 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 your ANSWER BOOK, for example 1.17 E. 4.1. C2Hs reacts with H2 to produce a hydrocarbon as represented below. C2Ha + H2 — hydrocarbon Which ONE of the following is the general formula of the hydrocarbon? A CnHen B CnHane1 Cc CnHant2 D = CrHan-2 (2) 1.2 The condensed structural formula of an organic compound is shown below. fe) G—0-H Crb—G—Chs CH3—C—CHs3 , Which ONE of the following is the correct IUPAC name of this compound? A 2,2,3-trimethylbutanoic acid B 2,3,3-trimethylbutanoic acid Cc 2,2,3,3-tetramethylpropanoic acid D 1,1,2,2-tetramethylpropanoic acid (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 4 FS/September 2020 Grade 12 Prep. Exam. 1.3. Hydrogen bonds ... A are intramolecular forces. B are stronger intermolecular forces than chemical bonds. Cc form between hydrogen atoms in non-polar molecules. D form between molecules in which hydrogen atoms are bonded to highly electronegative atoms. (2) 4.4. The reaction of sulphur dioxide and oxygen to form sulphur trioxide reaches equilibrium in a closed container according to the following balanced equation: 2S02(g) + O2x(g) = 2SO0s(g) The graph below shows how the percentage yield of SOs(g) at equilibrium changes with temperature. 4 % yield of SO3 at equilibrium Temperature (°C) > Which ONE of the following combinations is correct for the REVERSE REACTION? TYPE OF HEAT OF REACTION REACTION (AH) A | Exothermic Es0,.0, —Ego, B_ | Endothermic Eg, —Eso,.0, C | Exothermic Exo, Eso, 0, D | Endothermic Es0,10, —Ego, Copyright reserved (2) Please turn over

Downloaded from hlayiso.com Physica! Sciences P2 5 FS/September 2020 Grade 12 Prep. Exam. 1.5 1.6 Which ONE of the following combinations is correct for an endothermic reaction? HEAT OF THE POTENTIAL ENERGY REACTION (AH) OF PRODUCTS IS... A | positive less than that of reactants. B_ | positive more than that of reactants. C | negative less than that of reactants. D_ | negative more than that of reactants. (2) The reaction of calcium carbonate with EXCESS dilute hydrochloric acid is used to investigate reaction rate. The balanced equation for the reaction is: CaCOa(s) + 2HCf(aq) - CaCte(aq) + CO2(g) + H2O(2) Two experiments, I and II, are conducted under different reaction conditions. The results obtained are represented in the graphs below. sereeene Experiment I és Experiment II Ov =a $ Time Which ONE of the statements below explains the difference in the above graphs the best? In experiment II: A A greater volume of acid was used B More calcium carbonate was used Cc Acid of lower concentration was used D Calcium carbonate of larger surface area was used (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 6 FS/September 2020 Grade 12 Prep. Exam. 4.7. Consider the following balanced equation for a reaction at equilibrium. ICK(f) + Clo(g) = IChs(s) AH = - 106 kJ:mol!" Which ONE of the following changes in temperature and pressure will result in the HIGHEST yield of solid? TEMPERATURE PRESSURE Decrease Decrease Decrease Increase Increase Decrease Increase Increase 4.8. Which ONE of the following represents the products formed and the pH of the solution when ammonium chloride (NH4C£) undergoes hydrolysis? pace pH OF SOLUTION A HCt + OH" Above 7 B NH3 + OH™ Below 7 Cc NH, + OH” Above 7 D NH3 + H30* Below 7 Copyright reserved Please turn over

Downloaded from hlayiso.com 7 FS/September 2020 Physical Sciences P2 Grade 12 Prep. Exam. 1.9 The pH of the poison released when two different insects, X and Y, bite their prey, is given below. Insect X: pH =6 Insect Y: pH = 8 Which ONE of the following combinations gives the substances that will most probably bring relief from each of the insect bites? INSECT X INSECT Y A Oxalic acid Sodium hydroxide B Sodium hydrogen carbonate | Vinegar Cc Sodium hydroxide Sodium hydrogen carbonate D Vinegar Lemon juice 1.10 Consider the apparatus P, Q, R and S illustrated below. Which ONE of the following correctly links the above apparatus to the purpose for which it can be used? APPARATUS PURPOSE A P Measures the volume of acid added to base in a titration _ B Q Measures the amount of calcium carbonate needed in a rate-determining experiment Cc R Measures the volume of gas released in an experiment D s Measures 15 cm* of base to be used ina titration Copyright reserved (2) (2) {20} Please turn over

Downloaded from hlayiso.com Physical Sciences P2 8 FS/September 2020 Grade 12 Prep. Exam. QUESTION 2 (Start on a new page.) The letters A to E in the table below represent four organic compounds. A | Ethanoic acid B | CaH1oO H C2 Br H H H H H H O b | f | Lb | I tf ot dl — C—C—C—C—C—C-—-H H—G—E—C— 0H | {| [| ; H H 4H H H c D a a H—C—H H—C—H | | H—C—H H | H E | 4-methylhex-2-yne F | CeHis 2.1 Compounds A and B are heated in the presence of an acid catalyst. Write down the: 2.1.1 Type of reaction that takes place (1) 2.1.2 Hornologous series to which the organic product formed, belongs (1) 2.1.3 Structural formula of the organic product formed (2) 2.2. For compound A, write down the NAME of the: 2.2.1 Strongest intermolecular forces present (1) 2.2.2 Functional group (1) 2.3. Write down the GENERAL FORMULA of the homologous series to which compound B belongs. (1) 2.4 For compound C, write down the: 2.4.1 IUPAC name (2) 2.4.2 Structural formula of a FUNCTIONAL ISOMER of the SAME chain length (3) 2.5 Write down the IUPAC name of compound D. (3) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 9 FS/September 2020 Grade 12 Prep. Exam. 2.6 Consider compound E. 2.6.1 Is compound E a SATURATED or an UNSATURATED hydrocarbon? Give a reason for the answer. (2) 2.6.2 Write down the structural formula of compound E. (3) 2.7 During a cracking reaction of compound F, ONE inorganic product and TWO organic products are formed. Prop-1-ene is one of the organic products formed. 2.7.1 Define the term cracking reaction. (2) 2.7.2 Write down TWO reaction conditions needed for thermal cracking to take place. (2) 2.7.3 Write down the IUPAC name of the other organic product formed. (2) 2.7.4 To which homologous series does the organic product in QUESTION 2.7.3 belong? (1) 2.7.5 Write down the NAME or FORMULA of the inorganic product formed. (1) [28] Copyright reserved Please turn over

Downloaded from hlayiso.com FS/September 2020 Physical Sciences P2 Grade 12 Prep. Exam. QUESTION 3 (Start on a new page.) During a practical investigation, the boiling points of three compounds A, B and © 10 were determined and the results recorded in the table below. 3.1 3.2 3.3 3.4 25 3.6 3.7 3.8 COMPOUND SOEs aed c me iii A Alkane 1 AAS B Alkane 2 184 Cc Alcohol 2 351 Define the term boiling point. Write down the structural formula of the functional group of compound C. Is compound C a LIQUID or a GAS at 333 K? Which compound (A, B or C) has the highest vapour pressure? Give a reason for the answer. During the investigation, the results obtained for the compounds above are compared. Write down the INDEPENDENT VARIABLE when comparing the results obtained for the following compounds: 3.5.1. Compounds A and B 3.5.2 Compounds B and C Explain why compound A will evaporate faster than compound B. Refer to the TYPE and relative STRENGTHS of the intermolecular forces. is it fair to compare compound A with compound B? Write only YES or NO. (1) Give a reason for the answer to QUESTION 3.7 Copyright reserved (1) [13] Please turn over

Downloaded from hlayiso.com Physical Sciences P2 11 FS/September 2020 Grade 12 Prep. Exam. QUESTION 4 (Start on a new page.) The flow diagram below shows how a haloalkane (compound P) can be used to prepare other organic compounds. The letters A to F represent different organic reactions. Lit a A__, Alkene ts HoH —— Compound Q Compound P Cc F H20 D E Propan-1-ol Alcohol Compound R + Compound S 4.1 Ils compound P a PRIMARY, SECONDARY or TERTIARY haloalkane? Give a reason for the answer. (2) 4.2 Write down the IUPAC name of compound Q. (1) 4.3. State TWO reaction conditions for reaction F. (2) 4.4 Compounds R and S are structural isomers. 4.4.1 Define the term structural isomer. (2) 4.4.2 Are compounds R and S POSITIONAL, FUNCTIONAL or CHAIN isomers? (1) 4.4.3 Give a reason for the answer to QUESTION 4.4.2. (1) 4.4.4 Write down the structural formula of compound 8S. (2) 4.5 Write down the name of: 4.5.1. Addition reaction B (1) 4.5.2 Elimination reaction D (1) 4.5.3. Substitution reaction F (1) 4.6 Using structural formulae, write down a balanced equation for reaction E. (4) [18] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 12 FS/September 2020 Grade 12 Prep. Exam. QUESTION 5 (Start on a new page.) 5.1 Learners use the reaction of magnesium powder with dilute hydrochloric acid in an experiment. The balanced equation for the reaction is: Mg(s) + 2HCt(aq) + MgCfo(aq) + H2(g) Initially, they add 250 cm® hydrochloric acid (HC2) of concentration 0,3 mol:dm* to 1,2 g of magnesium powder in a test tube. The mass of the magnesium powder is recorded at regular time intervals. The sketch graph of mass against time below was obtained from the results. = N Mass of Mg (g) | I I 0 1 2 3 Time (min) 5.1.1 Define the term reaction rate. (2) 5.1.2 Write down the NAME or FORMULA of the limiting reagent in this reaction. Give a reason for the answer. (2) 5.1.3 Calculate the average rate of the reaction, in g-min", in the first 2 minutes if the mass of the magnesium decreases by 1,1 g in this time. (3) 5.1.4 Calculate the number of moles of unreacted hydrochloric acid in the test tube after 3 minutes. (6) 5.1.5 Copy the axes and the curve above into your ANSWER BOOK and label it A. (No values are needed on the axes.) On the same set of axes, sketch curve B that will be obtained if a catalyst is added to the reaction mixture. (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 13 FS/September 2020 Grade 12 Prep. Exam. 5.2 The Maxwell-Boltzmann distribution curves, P and Q, for a reaction at two DIEFERENT TEMPERATURES are shown below. The vertical axis is not labelled. 5.2.1 5.2.2 S20 5.2.4 5.2.5 Kinetic energy ann Activation energy State the TWO criteria, as described by the collision theory, that should be met by any chemical reaction before it can take place. (2) Write down a suitable label for the vertical axis shown above. (1) Write down the letter (v, w, x or y) that indicates the most probable kinetic energy of molecules in the reaction mixture represented by curve P. (1) Which curve, P or Q, represents the reaction taking place at the higher rate? Refer to the collision theory to explain the answer. (3) How will the addition of a catalyst to the reaction mixture affect each of the following? Write down INCREASE, DECREASE or REMAIN THE SAME. (a) The peak of curve P (1) (b) | The number of molecules with energy equal to or greater than the activation energy (1) [24] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 14 FS/September 2020 Grade 12 Prep. Exam. QUESTION 6 (Start on a new page.) The potential energy graph for the reaction of hydrogen with iodine is shown below. The balanced equation for the reaction is: Ha(g) + Ig) = 2HI(g) Potential energy (kJ) Reaction progress 6.1 Is the forward reaction EXOTHERMIC or ENDOTHERMIC? Give a reason for the answer. (2) 6.2 Define the term activation energy. (2) 6.3. In terms of R and $ shown on the graph, write down an expression for the: 6.3.1 Activation energy for the forward reaction (1) 6.3.2 Heat of reaction (AH) for the forward reaction (1) A catalyst is now added to the reaction mixture. 6.4 Redraw the above graph in your ANSWER BOOK and use a DOTTED LINE to show how the addition of a catalyst will influence the curve. No labels are required. (2) 6.5 How will the catalyst affect the time taken by the reaction to reach equilibrium? Write down only INCREASES, DECREASES or REMAINS THE SAME. (1) [9] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 15 FS/September 2020 Grade 12 Prep. Exam. QUESTION 7 (Start on a new page.) Excess sulphur and 3 mol oxygen gas are sealed in an empty 3 dm® container at a certain temperature. The reaction reaches equilibrium according to the following balanced equation: S(s) + O2(g) = SO2(g) AH < 0 7.1 Define the term chemical equilibrium. (2) 7.2. The equilibrium constant (Ke) for the reaction at this temperature is 2. 7.2.1 Calculate the number of moles of SO2(g) present at equilibrium. (7) 7.2.2 Calculate the equilibrium concentration of SO2(g). (2) 7.3. How will each of the following affect the yield of SO2(g)? Write down only INCREASES, DECREASES or REMAINS THE SAME. 7.3.1 More sulphur is added into the container. (1) 7.3.2 The pressure is increased by decreasing the volume of the container at constant temperature. (1) 7.4 The temperature is now changed and it is found that the equilibrium constant (Ke) increases. Did the temperature INCREASE or DECREASE? (1) 7.5 Explain the answer to QUESTION 7.4. (2) 7.6 How will the addition of a catalyst influence the equilibrium constant (Kc) of this reaction? Write down only INCREASES, DECREASES or REMAINS THE SAME. (1) [17] QUESTION 8 (Start on a new page.) 8.1 Sulphuric acid, H2SOs, ionises in two steps. The first step in this ionisation is represented by the following incomplete equation. H2SOa(aq) + H2O0(2) = Ampholyte P(aq) + H30*(aq) 8.1.1 Define the term ampholyte. (2) 8.1.2 For ampholyte P, write down the: (a) | NAME or FORMULA (1) (b) | NAME or FORMULA of its conjugate acid (1) (c) NAME or FORMULA of its conjugate base (1) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 16 FS/September 2020 Grade 12 Prep. Exam. 8.2 cm? A.0,1 mol-dm? sodium hydroxide solution, NaOH(aq), is prepared in a 100 volumetric flask. The sodium hydroxide solution is titrated with a 0,12 mol-dm? sulphuric acid solution, H2SO4(aq), using the apparatus illustrated below. 8.3 retort stand —————>] sulphuric acid Y sodium hydroxide It is found that 15 cm? of the HzSOu4(aq) neutralises an unknown volume of the NaOH(aq). The balanced equation for the reaction is: 2NaOH(aq) + H2SOa(aq) + NazSOa(aq) + 2H20(E) 8.2.1 Define the term strong base. (2) 8.2.2 Write down the name of the apparatus labelled: (a) X (1) (bo) ¥ (1) 8.2.3 Calculate the volume of sodium hydroxide that remains in ¥ after addition of 15 cm® sulphuric acid. (5) The excess sodium hydroxide solution in Y reacts with 0,4 g impure ammonium chloride, NH4C2, according to the following balanced equation: NaOH(aq) + NH4Ct(s) > NaCf(aq) + H20(t) + NHs(aq) Calculate the percentage impurities in the ammonium chloride. (7) [21] TOTAL: 150 Copyright reserved

Downloaded from hlayiso.com Physical Sciences P2 Grade 12 Prep. Exam. FS/September 2020 DATA FOR PHYSICAL SCIENCES GRADE 12 PAPER 2 (CHEMISTRY) GEGEWENS VIR FISIESE WETENSKAPPE GRAAD 12 VRAESTEL 2 (CHEMIE) TABLE 1: PHYSICAL CONSTANTS / TABEL 1: FISIESE KONSTANTES NAME / NAAM SYMBOL / SIMBOOL VALUE / WAARDE Standard pressure a 5 Standaarddruk p 1,013 x 10° Pa Molar gas volume at STP 3. 1 Molére gasvolume by STD Vm 22,4 dm*-mol Standard temperature 6 Standaardtemperatuur T 273 K Charge on electron a" Lading op elektron e 16x 10°C Avogadro's constant Na 6,02 x 10 mot" Avodadro se konstante TABLE 2: FORMULAE / TABEL 2: FORMULES n= wal M Ny Vv fe mu or/of c= Lue n=— MV V,, faVa _ Na = . CyV, My PH = -log[H30*] Kw = [H30*][OH] = 1 x 10°4 at/by 298 K @ fe 8 e@ fe 8 Fea = E cathode ~ E rode Esa = E ietode ~ E poco orlof 8 _ fe a @ _f8 8 Eee ~ E recuiction ~ E oration (Esa ~ E rectiaie ~ E cisidasie orlof 6 _ ¢e () @ re cc) Ea aaa Se agent — EE assngeaa ! Esa ~ E oksidoermiadet ~ E ecuscermidde! Copyright reserved

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