Technical Sciences Grade 12 P2 Gauteng Mock 2021 QP (Eng)

Downloaded from hlayiso.com GAUTENG DEPARTMENT OF EDUCATION PREPARATORY EXAMINATION 2021 11102 TECHNICAL SCIENCES PAPER 2 TIME: 1½ hours MARKS: 75 9 pages + 4 information sheets P.T.O.

Downloaded from hlayiso.com TECHNICAL SCIENCES 2 (Paper 2) 11102/21 INSTRUCTIONS AND INFORMATION 1. This question paper consists of FIVE questions. Answer ALL the questions in the ANSWER BOOK. 2. Start EACH question on a NEW page in the ANSWER BOOK. 3. Number the answers correctly according to the numbering system used in this question paper. 4. Leave ONE line between two sub-questions, e.g. between QUESTION 2.1 and QUESTION 2.2. 5. You may use a non-programmable calculator. 6. You are advised to use the attached INFORMATION SHEETS. 7. Round-off your FINAL numerical answers to a minimum of TWO decimal places. 8. Give brief motivations, discussions, etc., where required. 9. Write neatly and legibly. P.T.O.

Downloaded from hlayiso.com TECHNICAL SCIENCES 3 (Paper 2) 11102/21 QUESTION 1: MULTIPLE CHOICE QUESTIONS Various options are provided as possible answers to the following questions. Choose the correct answer and write only the letter (A–D) next to the question number (1.1 to 1.6) in the ANSWER BOOK, e.g. 1.7 D. 1.1 Which of the following hydrocarbons does not have structural isomers? A Butane B Pentane C Propane D Butene (2) 1.2 Which one of the following has the highest boiling point? A Hexane B Butane C Propane D Ethane (2) 1.3 Consider the following chemical reaction: C5H10 + HCℓ → C5H11Cℓ This type of reaction can best be described as ... A an addition reaction. B an acid-base reaction. C a substitution reaction. D a hydrogenation reaction. (2) P.T.O.

Downloaded from hlayiso.com TECHNICAL SCIENCES 4 (Paper 2) 11102/21 1.4 Which of the following organic compounds has the molecular formula C5H10O2? A Ethyl ethanoate B Butyl ethanoate C Ethyl propanoate D Propyl butanoate (2) 1.5 The following TWO statements regarding a voltaic cell are given below: I. An oxidation half reaction takes place at the cathode of the cell. II. Positive ions move from the salt bridge to the anode of the cell. Which of the following is true about the voltaic cell? A I only B II only C Neither I nor II D Both I and II (2) 1.6 Consider the following electrochemical cell reaction: 𝐶𝑢2+ (𝑎𝑞) + 𝑍𝑛(𝑠) → 𝐶𝑢(𝑠) + 𝑍𝑛2+ (𝑎𝑞) + 𝑒𝑛𝑒𝑟𝑔𝑦 A The copper metal is the anode of the cell. B Copper metal acts as the oxidizing agent. C The zinc metal is the anode of the cell. D Zinc metal acts as the oxidizing agent. (2) [12] P.T.O.

Downloaded from hlayiso.com TECHNICAL SCIENCES 5 (Paper 2) 11102/21 QUESTION 2 (Start on a new page.) Study the following table of organic molecules as represented by letter A to F below and answer the questions that follow. A Pent-2-ene B C Propylmethanoate D 2,4-dimethylhexane E F 2.1 Define a homologous series. (2) 2.2 Write down the letter representing the compound which … 2.2.1 is an aldehyde. (1) 2.2.2 has the general fomula CnH2n. (1) 2.2.3 is unsaturated. (1) 2.2.4 is a ketone. (1) 2.2.5 is a hydrocarbon. (1) P.T.O.

Downloaded from hlayiso.com TECHNICAL SCIENCES 6 (Paper 2) 11102/21 2.3 Write down the structural formula of: 2.3.1 Compound A (3) 2.3.2 Compound D (3) 2.4 Write down the following: 2.4.1 The name of the functional group of compound F (1) 2.4.2 The IUPAC name of compound B (2) [16] P.T.O.

Downloaded from hlayiso.com TECHNICAL SCIENCES 7 (Paper 2) 11102/21 QUESTION 3 (Start on a new page.) The first six members of the alkanes occur as gases and liquids at normal temperatures. Alkanes are currently our most important fuels, but the use of alcohols as a renewable energy source is becoming more and more important. Alcohols are liquids that might be a solution to the energy crisis. 3.1 Which chemical property of alkanes and alcohols make them suitable to be used as fuels? (2) 3.2 The table below shows the boiling point of the first six alkanes and the first six alcohols. Alkane Boiling point Alcohol Boiling point (˚C) (˚C) methane - 164 methanol 65 ethane - 89 ethanol 79 propane - 42 1-propanol 97 butane - 0,5 1-butanol 117 pentane 36 1-pentanol 138 hexane 69 1-hexanol 156 Draw a graph of boiling points versus the number of carbon atoms for the first six ALCOHOLS. Choose 50° C and 1 carbon atom as the origin and use an appropriate scale. Plot the points and draw the best curve through the points. (4) 3.3 What trend in boiling point can be observed from the graph? (2) 3.4 Provide a reason for the trend mentioned in QUESTION 3.3 by referring to the type of intermolecular forces. (2) 3.5 Explain, referring to the type of intermolecular forces, why the boiling points of alcohols are higher than the boiling points of alkanes. (2) 3.6 People are always cautioned to keep liquids such as petrol (a mixture of alkanes) out of the reach of children. Use the boiling points of alkanes to justify this precaution. (2) [14] P.T.O.

Downloaded from hlayiso.com TECHNICAL SCIENCES 8 (Paper 2) 11102/21 QUESTION 4 (Start on a new page.) The flow diagram below shows the interconversion between alcohols, alkenes and haloalkanes. The letters A – F represent addition or substitution. propene F B E A C alcohol haloalkane D 4.1 What type of reaction is represented by F? Write down only ADDITION or SUBSTITUTION. (1) 4.2 Use structural formulae and write a balanced chemical equation for reaction F to show the formation of the major product. (3) 4.3 Reaction E is sometimes referred to as dehydration. Write down the FORMULA of the substance eliminated during dehydration. (1) 4.4 Letter C represents the reaction of the alcohol with NaBr(aq) in the presence of sulphuric acid as a catalyst. 4.4.1 Write down the structural formula for the organic product of this reaction. (1) 4.4.2 What type of reaction is represented by C? Write down only ADDITION or SUBSTITUTION. (1) 4.5 The haloalkane can be converted to alcohol through reaction D, or to propene through reaction A. 4.5.1 What type of reaction is represented by B? Write down only ADDITION or SUBSTITUTION. (1) 4.5.2 What type of reaction is represented by D? Write down only ADDITION or SUBSTITUTION. (1) 4.5.3 Under what condition will reaction B take place? (1) [10] P.T.O.

Downloaded from hlayiso.com TECHNICAL SCIENCES 9 (Paper 2) 11102/21 QUESTION 5 (Start on a new page.) 5.  The diagram below shows how the voltaic cell is constructed by placing a copper plate in a beaker containing copper sulphate solution.  The zinc plate is then placed in a beaker containing zinc sulphate solution.  The copper plate is then connected to the zinc by a copper wire. 5.1 Write TWO conditions for this type of voltaic cell. (2) 5.2 In which direction do the electrons flow? (Choose from Cu to Zn or Zn to Cu.) (1) 5.3 Write down the energy conversions for this cell. (2) 5.4 Write ONE function of the salt bridge that connects the two half cells. (1) 5.5 Define the term reducing agent. (2) 5.6 Write down the oxidation half reaction for the cell. (2) 5.7 Write down the reduction half reaction for the cell. (2) 5.8 Write down a net balanced chemical reaction for the cell. (3) 5.9 Identify the anode and cathode in this cell. (2) 5.10 Write down the cell notation of this cell. (3) 5.11 Use the table of standard reduction potentials to calculate the initial EMF of this cell. (3) [23] TOTAL: 75 END

Downloaded from hlayiso.com TECHNICAL SCIENCES 10 (Paper 2) 11102/21 DATA FOR TECHNICAL SCIENCES GRADE 12 PAPER 2 TABLE 1: PHYSICAL CONSTANTS NAME SYMBOL VALUE Standard pressure p 1,01 x 105 Pa Standard temperature T 0 °C/273 K TABLE 2: FORMULAE Eθcell  Eθcathode  Eθanode E θcell  E reduction θ  E θoxidation E θcell  E θoxidisingagent  E reducing θ agent TABLE 3: ELECTROCHEMISTRY Emf Eθcell  Eθcathode  Eθanode / E θsel  E katode θ  E θanode or E θcell  E reduction θ  E θoxidation / E θsel  E reduksie θ  E θoksidasie or E θcell  E θoxidisingagent  E reducing θ agent / E sel  E oksideermiddel  E reduseermiddel θ θ θ

Downloaded from hlayiso.com TECHNICAL SCIENCES 11 (Paper 2) 11102/21 TABLE 4A: STANDARD REDUCTION POTENTIALS/ TABEL 4A: STANDAARD-REDUKSIEPOTENSIALE Half-reactions/Halfreaksies E θ (V) F2(g) + 2e ⇌ 2F + 2,87 Co3+ + e ⇌ Co2+ + 1,81 H2O2 + 2H+ +2e ⇌ 2H2O +1,77  MnO 4 + 8H+ + 5e ⇌ Mn2+ + 4H2O + 1,51 Cℓ2(g) + 2e ⇌ 2Cℓ + 1,36 2 Cr2O 7 + 14H+ + 6e ⇌ 2Cr3+ + 7H2O + 1,33  ⇌ O2(g) + 4H+ + 4e 2H2O + 1,23 MnO2 + 4H+ + 2e ⇌ Mn2+ + 2H2O + 1,23 Pt2+ + 2e ⇌ Pt + 1,20 Br2(ℓ) + 2e ⇌ 2Br + 1,07 NO 3 + 4H+ + 3e Increasing oxidising ability/Toenemende oksiderende vermoë ⇌ NO(g) + 2H2O + 0,96 Increasing reducing ability/Toenemende reduserende vermoë Hg2+ + 2e ⇌ Hg(ℓ) + 0,85 Ag+ + e ⇌ Ag + 0,80  NO 3 + 2H+ + e ⇌ NO2(g) + H2O + 0,80 Fe3+ + e ⇌ Fe2+ + 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 2 SO 4 + 4H+ + 2e ⇌ SO2(g) + 2H2O + 0,17  ⇌ Cu+ Cu2+ + e + 0,16 Sn4+ + 2e ⇌ Sn2+ + 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 Ni2+ + 2e ⇌ Ni  0,27 Co2+ + 2e ⇌ Co  0,28 Cd2+ + 2e ⇌ Cd  0,40 Cr3+ + e ⇌ Cr2+  0,41 Fe2+ + 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 Mg2+ + 2e ⇌ Mg  2,36 Na+ + e ⇌ Na  2,71 Ca2+ + 2e ⇌ Ca  2,87 Sr2+ + 2e ⇌ Sr  2,89 Ba2+ + 2e ⇌ Ba  2,90 Cs+ + e- ⇌ Cs - 2,92 K+ + e ⇌ K  2,93 Li+ + e ⇌ Li  3,05

Downloaded from hlayiso.com TECHNICAL SCIENCES 12 (Paper 2) 11102/21 TABLE 4B: STANDARD REDUCTION POTENTIALS TABEL 4B: STANDAARD-REDUKSIEPOTENSIALE E θ (V) Half-reactions/Halfreaksies Li+ + e ⇌ Li  3,05 K+ + e ⇌ K  2,93 Increasing reducing ability/Toenemende reduserende vermoë Cs+ + e ⇌ Cs  2,92 Increasing oxidising ability/Toenemende oksiderende vermoë Ba2+ + 2e ⇌ Ba  2,90 Sr2+ + 2e ⇌ Sr  2,89 Ca2+ + 2e ⇌ Ca  2,87 Na+ + e ⇌ Na  2,71 Mg2+ + 2e ⇌ Mg  2,36 Aℓ3+ + 3e ⇌ Aℓ  1,66 Mn2+ + 2e ⇌ Mn  1,18 Cr2+ + 2e ⇌ Cr  0,91 2H2O + 2e ⇌ H2(g) + 2OH  0,83 Zn2+ + 2e ⇌ Zn  0,76 Cr3+ + 3e ⇌ Cr  0,74 Fe2+ + 2e ⇌ Fe  0,44 Cr3+ + e ⇌ Cr2+  0,41 Cd2+ + 2e ⇌ Cd  0,40 Co2+ + 2e ⇌ Co  0,28 Ni2+ + 2e ⇌ Ni  0,27 Sn2+ + 2e ⇌ Sn  0,14 Pb2+ + 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 Cu2+ + e ⇌ Cu+ + 0,16 2 SO 4 + 4H+ + 2e ⇌ SO2(g) + 2H2O + 0,17 Cu2+ + 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 ⇌ H2 O 2 + 0,68 Fe3+ + e ⇌ Fe2+ + 0,77 NO 3 + 2H+ + e ⇌ NO2(g) + H2O + 0,80 Ag+ + e ⇌ Ag + 0,80 Hg2+ + 2e ⇌ Hg(ℓ) + 0,85 NO 3 + 4H+ + 3e ⇌ NO(g) + 2H2O + 0,96   Br2(ℓ) + 2e ⇌ 2Br + 1,07 Pt2+ + 2 e ⇌ Pt + 1,20 MnO2 + 4H+ + 2e ⇌ Mn2+ + 2H2O + 1,23 O2(g) + 4H+ + 4e ⇌ 2H2O + 1,23 2 Cr2O 7 + 14H+ + 6e ⇌ 2Cr3+ + 7H2O + 1,33   Cℓ2(g) + 2e ⇌ 2Cℓ + 1,36  MnO 4 + 8H+ + 5e ⇌ Mn2+ + 4H2O + 1,51 H2O2 + 2H+ +2 e ⇌ 2H2O +1,77 Co3+ + e ⇌ Co2+ + 1,81 F2(g) + 2e ⇌ 2F + 2,87

Downloaded from hlayiso.com TECHNICAL SCIENCES 13 (Paper 2) 11102/21 TABLE 5: THE PERIODIC TABLE OF ELEMENTS/TABEL 5: DIE PERIODIEKE TABEL VAN ELEMENTE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 (I) (II) (III) (IV) (V) (VI) (VII) (VIII) KEY 1 Atomic number 2 2,1 H He 1 29 4 3 4 5 6 7 8 9 10 Electronegativity 1,9 Cu Symbol 1,0 Li 1,5 Be 2,0 B 2,5 C 3,0 N 3,5 O 4,0 F Ne 63,5 7 9 11 12 14 16 19 20 11 12 13 14 15 16 17 18 0,9 Na 1,2 Mg Approximate relative atomic mass 1,5 Aℓ 1,8 Si 2,1 P 2,5 S 3,0 Cℓ Ar 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 0,8 K 1,0 Ca 1,3 Sc 1,5 Ti 1,6 V 1,6 Cr 1,5 Mn 1,8 Fe 1,8 Co 1,8 Ni 1,9 Cu 1,6 Zn 1,6 Ga 1,8 Ge 2,0 As 2,4 Se 2,8 Br Kr 39 40 45 48 51 52 55 56 59 59 63,5 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 0,8 Rb 1,0 Sr 1,2 Y 1,4 Zr Nb 1,8 Mo 1,9 Tc 2,2 Ru 2,2 Rh 2,2 Pd 1,9 Ag 1,7 Cd 1,7 In 1,8 Sn 1,9 Sb 2,1 Te 2,5 I Xe 86 88 89 91 92 96 101 103 106 108 112 115 119 122 128 127 131 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 0,7 Cs 0,9 Ba La 1,6 Hf Ta W Re Os Ir Pt Au Hg 1,8 Tℓ 1,8 Pb 1,9 Bi 2,0 Po 2,5 At Rn 133 137 139 179 181 184 186 190 192 195 197 201 204 207 209 87 88 89 0,7 Fr 0,9 Ra Ac 58 59 60 61 62 63 64 65 66 67 68 69 70 71 226 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 140 141 144 150 152 157 159 163 165 167 169 173 175 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr 232 238