Physical Sciences Grade 12 Free State Prelim 2024 QP

Downloaded from hlayiso.com bm PREPARATORY EXAMINATION GRADE 12 PHYSICAL SCIENCES P2 (CHEMISTRY) SEPTEMBER 2024 MARKS: 150 TIME: 3 HOURS This question paper consists of 13 pages and 4 data sheets. Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 2 FS/September 2024 Grade 12 Prep. Exam. INSTRUCTIONS AND INFORMATION 1. Write your name and other applicable information in the appropriate spaces on the ANSWER BOOK. 2. The question paper consists of NINE questions. Answer ALL the questions in the ANSWER BOOK. 3. Start EACH question on a NEW page in the ANSWER BOOK. 4. Number the answers correctly according to the numbering system used in this question paper. 5. Leave ONE line between two sub-questions, for example between QUESTION 3.1 and QUESTION 3.2. 6. You may use a non-programmable pocket calculator. 7. You may use appropriate mathematical instruments. 8. Show ALL formulae and substitutions in ALL calculations. 9. Round off your FINAL numerical answers to a minimum of TWO decimal places where necessary. 10. Give brief motivations, discussions, etc. where required. 11. You are advised to use the attached DATA SHEETS. 12. Write neatly and legibly. Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 3 FS/September 2024 Grade 12 Prep. Exam. QUESTION 1: MULTIPLE-CHOICE QUESTIONS Various options are provided as possible answers to the following questions. Each question has only ONE correct answer. Choose the answer and write only the letter (A–D) next to the question numbers (1.1 to 1.10) in your ANSWER BOOK, for example, 1.11 E. 1.1 The condensed structural formula of an organic molecule is given as: CH3CH(CH3)CH2CH3 The molecule is … A unsaturated. B saturated. C a straight alkane. D a straight alkene. (2) 1.2 Consider the organic structure below: O CH3 C O CH3 The IUPAC name of its FUNCTIONAL ISOMER is … A methyl ethanoate. B propanoic acid. C ethyl methanoate. D ethanoic acid. (2) 1.3 Consider the following organic molecule: CH(CH3)2CH2CH(CH3)CH3 The correct IUPAC name is … A 1,1,4-trimethylbutane. B 2-methyl-3,3-dimethylbutane. C 2,4-dimethylpentane. D 2,2,4-trimethylpentane. (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 4 FS/September 2024 Grade 12 Prep. Exam. 1.4 While a chemical reaction takes place, the rate of the reaction … A remains the same. B decreases because the concentration of products decreases. C increases because the concentration of reactants increases. D decreases because the concentration of reactants decreases. (2) 1.5 Consider the following hypothetical reaction: A2 + B ⇌ A2B H < 0 The activation energy (EA) for this reaction is 100 kJ∙mol-1. For the reverse reaction … A EA is equal to 100 kJ∙mol-1. B EA is greater than 100 kJ∙mol-1. C EA is less than 100 kJ∙mol-1. D EA and H are equal. (2) 1.6 Write down the conjugate base of HCℓO4. − A HClO3 − B HClO4 − C ClO4 D H2CℓO4 (2) 1.7 A solution of sodium hydroxide … A turns bromothymol blue to yellow. B is acidic. C turns phenolphthalein to colourless. D is basic. (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 5 FS/September 2024 Grade 12 Prep. Exam. 1.8 A piece of magnesium ribbon reacts with excess hydrochloric acid according to the following balanced equation: Mg(s) + 2HCℓ(aq) → MgCℓ2(aq) + H2(g) Which ONE of the following is an oxidising agent? A Cℓ- B Mg2+ C H+ D H2 (2) 1.9 In a galvanic cell the salt bridge … A is responsible for the charge balance to be maintained in the cell. B allows for the movement of electrons from one half-cell to the other. C allows the mixing of the two solutions from different half-cells. D is not necessary for the optimal functioning of the cell. (2) 1.10 What is the energy conversion in an electrolytic cell? A Electrical to chemical B Chemical to electrical C Electrical to mechanical D Chemical to mechanical (2) [20] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 6 FS/September 2024 Grade 12 Prep. Exam. QUESTION 2 (Start on a new page.) The letters A to E in the table below represent organic compounds. H A H C H B Propyl ethanoate H Cl H H H C C H H C H H H H H D Propanal H C C C C C C H H H H H O Cl H H E 3,3-difloro-2-methylpentane 2.1 Write down the letter(s) representing: 2.1.1 A compound with the general formula CnH2n+2 (1) 2.1.2 A haloalkane (1) 2.1.3 A functional isomer of a ketone (1) 2.2 For compound C, write down the: 2.2.1 The type of alcohol it is, and give a reason for the answer. (2) 2.2.2 IUPAC name (3) 2.2.3 Name of its functional group (1) 2.3 For compound B, write down the: 2.3.1 Structural formulae of the TWO organic compounds it is formed from (4) 2.3.2 Structural formula of the functional group of its functional isomer (1) 2.4 Write down the structural formula of Compound E. (3) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 7 FS/September 2024 Grade 12 Prep. Exam. 2.5 Compound A undergoes complete combustion according to the following balanced equation: CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) During the combustion, 2,75 kg of carbon dioxide is formed. Calculate the mass of CH4 needed for this reaction. (5) [22] QUESTION 3 (Start on a new page.) The boiling points of four organic compounds at a specific pressure are compared. COMPOUND BOILING POINT (°C) A Pentane 36 B 2-methylbutane 28 C 2,2-dimethylpropane 10 D Pentanal 103 E Butanoic acid … 3.1 Define the term boiling point. (2) 3.2 Consider compounds A to C. 3.2.1 Fully explain the trend in boiling points from compound A to C. (4) 3.2.2 Which compound will have the highest vapour pressure? (1) 3.2.3 Explain your answer to QUESTION 3.2.2. (1) 3.3 Compounds D and E are compared. Is the boiling point of compound E GREATER THAN, SMALLER THAN or EQUAL TO 103°C? Fully explain the answer. (4) 3.4 Is the comparison in QUESTION 3.3 fair? (1) 3.5 Explain the answer to QUESTION 3.4. (1) [14] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 8 FS/September 2024 Grade 12 Prep. Exam. QUESTION 4 (Start on a new page.) The flow diagram below shows the steps in the preparation of an alcohol from compound Y, which is a SATURATED HYDROCARBON. Br2 Compound Y Compound Z Reaction I, Reaction II halogenation An alkene Reaction III H O 2 Compound X C3H6O2 Ethanol Reaction IV 4.1 Explain the term halogenation. (2) 4.2 For reaction I, write down: 4.2.1 ONE reaction condition (1) 4.2.2 The formula of the inorganic product (1) 4.3 For reaction II, write down the balanced equation using CONDENSED STRUCTURAL FORMULAE. (5) 4.4 Write down the name of reaction III. (1) In reaction IV, C3H6O2 is formed when ethanol reacts with compound X. 4.5 Write down the IUPAC name of compound X. (2) 4.6 Write down the name of reaction IV. (1) 4.7 Using STRUCTURAL FORMULAE, write down the balanced equation for this reaction. (4) [17] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 9 FS/September 2024 Grade 12 Prep. Exam. QUESTION 5 (Start on a new page.) Grade 12 learners use a reaction of CaCO3 with EXCESS HCℓ to investigate the relationship between concentration and rate of reaction. The balanced equation for the reaction is: CaCO3(s) + 2HCℓ(aq) → CaCℓ2(aq) + CO2(g) + H2O(ℓ) They conduct the experiment twice, each with a different concentration of HCℓ. A decrease in the mass of the flask and the content is represented in the table below. EXPERIMENT TIME(s) 0 30 60 90 120 150 180 Mass of flask 1 and contents (g) 270 268,4 267,4 266,75 266,3 266 266 Mass of flask 2 and contents (g) 270 269 268,4 268,1 268 268 268 5.1 Write down the name of the apparatus used for measuring the mass. (1) 5.2 Write down the NAME of the limiting reagent. (1) 5.3 Define the term rate of reaction. (2) 5.4 For experiment 1, calculate the rate of reaction in mol∙s-1 in the first 30 s. (5) 5.5 In which experiment did the learner use a higher concentration of HCℓ? (1) 5.6 Use the collision theory to explain the answer to QUESTION 5.5. (3) [13] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 10 FS/September 2024 Grade 12 Prep. Exam. QUESTION 6 (Start on a new page.) 6.1 Ammonia gas is produced by pouring nitrogen gas and hydrogen gas in an empty container and allowed to react in a closed container according to the following balanced equation: N2(g) + 3H2(g) ⇌ 2NH3(g) The graph of the rate of forward and reverse reactions is indicated below. Rate of reaction A B C D Time(s) 6.1.1 Define the term chemical equilibrium. (2) 6.1.2 Identify the change made at time B. (2) 6.1.3 There was a temperature change at time C, while the pressure was kept constant. (a) How did the temperature change? Write down only INCREASED or DECREASED. (1) (b) Is the forward reaction ENDOTHERMIC or EXOTHERMIC? (1) (c) Use Le Chatelier's principle to explain the answer to QUESTION 6.1.3 (b). (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 11 FS/September 2024 Grade 12 Prep. Exam. 6.2 The decomposition reaction of nitrosyl chloride (NOCℓ) is represented below: 2NOCℓ(g) ⇌ 2NO(g) + Cℓ2(g) At a temperature of 50°C, 4 mol of NOCℓ is placed in a 2 dm3 container. At equilibrium, it was found that 0,9 mol·dm-3 of NO was formed. 6.2.1 Define the term reversible reaction. (1) 6.2.2 Calculate the value of KC at 50°C. (7) [16] QUESTION 7 (Start on a new page.) 7.1 According to the balanced equation below, A dilute solution of HCℓ is used in titration against an ammonia solution. HCℓ(aq) + NH3(aq) → NH4Cℓ(aq) 7.1.1 Define the term hydrolysis. (2) 7.1.2 Will the final solution be ACIDIC or BASIC? (1) 7.1.3 Write down a balanced chemical equation that explains the answer to QUESTION 7.1.2. (3) 7.2 For the above titration, 25 cm3 of a 0,1 mol·dm-3 NH3 solution is titrated against 40 cm3 HCℓ solution. 7.2.1 Is HCℓ a STRONG or a WEAK acid? (1) 7.2.2 Explain the answer to QUESTION 7.2.1. (2) 7.2.3 Write down the name of the indicator that is most suitable for this reaction. (1) 7.2.4 Explain your choice of indicator. (2) 7.2.5 Calculate the number of moles of NH3 in 25 cm3 of the ammonia. (3) 7.2.6 Calculate the pH of the final solution if the concentration of the original HCℓ was 0,1 mol·dm-3. (8) [23] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 12 FS/September 2024 Grade 12 Prep. Exam. QUESTION 8 (Start on a new page.) The following balanced chemical equation represents a reaction taking place when a galvanic cell is in operation under STANDARD CONDITIONS. The initial reading on the voltmeter is 0,14V. 6Cℓ-(aq) + 2Au3+(aq) → 3Cℓ2(g) + 2Au(s) 8.1 Write down TWO standard conditions under which it operates. (2) 8.2 For this cell, write down the: 8.2.1 Name or formula of the electrolyte that can be used in the salt bridge (2) 8.2.2 Reducing agent (1) 8.2.3 Cell notation (3) 8.3 Calculate the standard reduction potential of Au. (4) [12] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 13 FS/September 2024 Grade 12 Prep. Exam. QUESTION 9 (Start on a new page.) The simplified diagram below represents the electrolysis of a concentrated sodium chloride solution. Carbon rods Y X NaCℓ(aq) The balanced equation for the reaction taking place in the above cell is: 2NaCℓ(aq) + 2H2O(ℓ) → 2NaOH(aq) + H2(g) + Cℓ2(g) 9.1 Define the term electrolysis. (2) 9.2 Which electrode is the anode? Write down only X or Y . (1) 9.3 Write down the half-reaction that takes place at: 9.3.1 Electrode X (2) 9.3.2 Electrode Y (2) 9.4 A current of 0,5 A is applied over a period of 5 hours. Calculate the volume of chlorine gas at STP that is formed during this time. (6) [13] TOTAL: 150 Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 FS/September 2024 Grade 12 Prep. Exam. 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 p 1,013 x 105 Pa Standaarddruk Molar gas volume at STP Vm 22,4 dm3 ∙mol-1 Molêre gasvolume by STD Standard temperature T 273 K Standaardtemperatuur Charge on electron e -1,6 x 10-19 C Lading op elektron Avogadro's constant NA 6,02 x 1023 mol-1 Avogadro-konstante TABLE 2: FORMULAE / TABEL 2: FORMULES m N n= n= M NA n 𝑚 V c= OR/OF 𝑐 = n= V 𝑀𝑉 Vm ca Va na + = pH = -log[H3 O ] cb Vb nb + Kw = [H3 O ][OH- ] = 1x10-14 at/by 298 K Eθcell = Eθcathode - Eθanode Eθsel = Eθkatode - Eθanode OR OF Eθcell = Eθreduction - Eθoxidation Eθsel = Eθreduksie - Eθoksidasie OR OF Eθcell = Eθoxidising agent - Eθredusing agent Eθsel = Eθoksideermiddel - Eθreduseermiddel Q Q n= where n is the number of electrons I= qe ∆t waar n die aantal elektrone is Copyright reserved Please turn over

Physical Sciences P2 Downloaded from hlayiso.com FS/September 2024 Grade 12 Prep. Exam. TABLE 3: THE PERIODIC TABLE OF ELEMENTS Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 FS/September 2024 Grade 12 Prep. Exam. TABLE 4A: STANDARD REDUCTION POTENTIALS TABEL 4A: STANDAARD-REDUKSIEPOTENSIALE Half-reactions / Halfreaksies (V) F2(g) + 2e− ⇌ 2F− + 2,87 Co3+ + e− ⇌ Co2+ + 1,81 H2O2 + 2H +2e + − ⇌ 2H2O +1,77 MnO + 8H+ + 5e− ⇌ Mn2+ + 4H2O + 1,51 Cℓ2(g) + 2e− ⇌ 2Cℓ− + 1,36 Cr2O + + 14H + 6e − ⇌ 2Cr 3+ + 7H2O + 1,33 O2(g) + 4H + 4e+ − ⇌ 2H2O + 1,23 MnO2 + 4H+ + 2e− ⇌ Mn2+ + 2H2O + 1,23 2+ Pt + 2e − ⇌ Pt + 1,20 Br2(ℓ) + 2e− ⇌ 2Br− + 1,07 NO + 4H+ + 3e− ⇌ NO(g) + 2H2O + 0,96 Hg2+ + 2e− ⇌ Hg(ℓ) + 0,85 Ag + e + − ⇌ Ag + 0,80 NO + 2H + e + − ⇌ NO2(g) + H2O + 0,80 Increasing oxidising ability / Toenemende oksiderende vermoë Increasing reducing ability / Toenemende reduserende vermoë Fe + e 3+ − ⇌ Fe 2+ + 0,77 O2(g) + 2H+ + 2e− ⇌ H2O2 + 0,68 I2 + 2e− ⇌ 2I− + 0,54 Cu+ + e− ⇌ Cu + 0,52 SO2 + 4H+ + 4e− ⇌ S + 2H2O + 0,45 2H2O + O2 + 4e− ⇌ 4OH− + 0,40 Cu2+ + 2e− ⇌ Cu + 0,34 SO + + 4H + 2e − ⇌ SO2(g) + 2H2O + 0,17 Cu2+ + e− ⇌ Cu+ + 0,16 Sn4+ + 2e− ⇌ Sn 2+ + 0,15 S + 2H+ + 2e− ⇌ H2S(g) + 0,14 + 2H + 2e − ⇌ H2(g) 0,00 Fe3+ + 3e− ⇌ Fe − 0,06 Pb2+ + 2e− ⇌ Pb − 0,13 Sn2+ + 2e− ⇌ Sn − 0,14 Ni 2+ + 2e− ⇌ Ni − 0,27 Co2+ + 2e− ⇌ Co − 0,28 Cd 2+ + 2e− ⇌ Cd − 0,40 Cr3+ + e− ⇌ Cr2+ − 0,41 2+ Fe + 2e − ⇌ Fe − 0,44 Cr3+ + 3e− ⇌ Cr − 0,74 Zn2+ + 2e− ⇌ Zn − 0,76 2H2O + 2e − ⇌ H2(g) + 2OH − − 0,83 Cr2+ + 2e− ⇌ Cr − 0,91 Mn2+ + 2e− ⇌ Mn − 1,18 Aℓ3+ + 3e− ⇌ Aℓ − 1,66 Mg 2+ + 2e− ⇌ Mg − 2,36 Na+ + e− ⇌ Na − 2,71 Ca 2+ + 2e− ⇌ Ca − 2,87 Sr2+ + 2e− ⇌ Sr − 2,89 2+ Ba + 2e − ⇌ Ba − 2,90 Cs+ + e- ⇌ Cs - 2,92 K+ + e− ⇌ K − 2,93 Li+ + e− ⇌ Li − 3,05 Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2 FS/September 2024 Grade 12 Prep. Exam. TABLE 4B: STANDARD REDUCTION POTENTIALS TABEL 4B: STANDAARD-REDUKSIEPOTENSIALE Half-reactions / Halfreaksies (V) + Li + e − ⇌ Li − 3,05 K+ + e− ⇌ K − 2,93 Cs + e + − ⇌ Cs − 2,92 Ba2+ + 2e− ⇌ Ba − 2,90 2+ Sr + 2e − ⇌ Sr − 2,89 Ca2+ + 2e− ⇌ Ca − 2,87 Na+ + e− ⇌ Na − 2,71 Mg 2+ + 2e − ⇌ Mg − 2,36 Aℓ3+ + 3e− ⇌ Aℓ − 1,66 Mn 2+ + 2e − ⇌ Mn − 1,18 Cr2+ + 2e− ⇌ Cr − 0,91 2H2O + 2e − ⇌ H2(g) + 2OH − − 0,83 Zn2+ + 2e− ⇌ Zn − 0,76 Increasing oxidising ability / Toenemende oksiderende vermoë Increasing reducing ability / Toenemende reduserende vermoë Cr 3+ + 3e − ⇌ Cr − 0,74 Fe2+ + 2e− ⇌ Fe − 0,44 Cr + e 3+ − ⇌ Cr2+ − 0,41 Cd2+ + 2e− ⇌ Cd − 0,40 Co2+ + 2e− ⇌ Co − 0,28 Ni 2+ + 2e − ⇌ Ni − 0,27 Sn2+ + 2e− ⇌ Sn − 0,14 2+ Pb + 2e − ⇌ Pb − 0,13 Fe3+ + 3e− ⇌ Fe − 0,06 2H+ + 2e− ⇌ H2(g) 0,00 S + 2H+ + 2e− ⇌ H2S(g) + 0,14 Sn4+ + 2e− ⇌ Sn2+ + 0,15 Cu 2+ − +e ⇌ Cu+ + 0,16 SO + 4H+ + 2e− ⇌ SO2(g) + 2H2O + 0,17 Cu 2+ + 2e − ⇌ Cu + 0,34 2H2O + O2 + 4e− ⇌ 4OH− + 0,40 SO2 + 4H + 4e+ − ⇌ S + 2H2O + 0,45 Cu+ + e− ⇌ Cu + 0,52 I2 + 2e − ⇌ 2I − + 0,54 O2(g) + 2H + 2e + − ⇌ H2O2 + 0,68 Fe 3+ − +e ⇌ Fe2+ + 0,77 NO + 2H+ + e− ⇌ NO2(g) + H2O + 0,80 Ag + e + − ⇌ Ag + 0,80 Hg2+ + 2e− ⇌ Hg(ℓ) + 0,85 NO + 4H+ + 3e− ⇌ NO(g) + 2H2O + 0,96 Br2(ℓ) + 2e− ⇌ 2Br− + 1,07 Pt 2+ +2e − ⇌ Pt + 1,20 MnO2 + 4H + 2e + − ⇌ Mn2+ + 2H2O + 1,23 O2(g) + 4H+ + 4e− ⇌ 2H2O + 1,23 Cr2O + + 14H + 6e − ⇌ 2Cr 3+ + 7H2O + 1,33 Cℓ2(g) + 2e − ⇌ 2Cℓ − + 1,36 MnO + 8H+ + 5e− ⇌ Mn2+ + 4H2O + 1,51 H2O2 + 2H +2 e + − ⇌ 2H2O +1,77 Co 3+ − +e ⇌ Co 2+ + 1,81 Copyright reserved F2(g) + 2e− ⇌ 2F− + 2,87 Please turn over