Technical Sciences Grade 12 P2 Gauteng Prelim 2024 Memo

Downloaded from hlayiso.com PREPARATORY EXAMINATION 2024 MARKING GUIDELINES TECHNICAL SCIENCES (PAPER 2) (11102) 6 pages

Downloaded from hlayiso.com 11102/24 QUESTION 1 1.1 C  (2) 1.2 B  (2) 1.3 C  (2) 1.4 D  (2) 1.5 D  (2) [10] QUESTION 2 2.1 A series of organic compounds that can be described by the same general formula and where each member differs from the next by CH2 group.  (0 or 2 marks) OR A series of organic compounds that can be described by the same general formula. OR A series of organic compounds where each member differs from the next by CH2 group. (2) 2.2 2.2.1 B (1) 2.2.2 E (1) 2.2.3 H (1) 2.3 2.3.1 Pent-2-ene OR 2-Pentene Marking criteria: • Pentene  • Position of functional group  NOTE: • If the hyphen was omitted then only ½ • If the position was omitted ½ (2) 2.3.2 Ethyl butanoate Marking criteria: • Ethyl  • Butanoate  (2) 2

Downloaded from hlayiso.com 11102/24 2.4 2.4.1 Marking criteria: • Position of functional group  • Whole structure correct  NOTE: • Any hydrogen bond or atom missing MAX ½ • 𝐶𝐶𝐶𝐶 can either be on the second carbon from the left OR right (2) Marking criteria: 2.4.2 • Whole structure  NOTE: The double bond can either be on Carbon 1 from left OR carbon 1 from right (1) 2.4.3 Marking criteria: • Double bond  • Whole structure correct  NOTE: • Any hydrogen bond or atom missing MAX ½ (2) [14] QUESTION 3 3.1 The property of a fluid to oppose relative motion between the two adjacent layers.  (0 or 2 marks) (2) 3.2 Flow time or Viscosity  (1) 3.3 A OR Propane (1) 3.4 London forces  (1) 3.5 C OR Pentane (1) 3.6 Pentane has the longest chain length which means that the London forces are stronger  so more energy is required to overcome the intermolecular forces  Marking criteria: • Negative marking from QUESTION 3.5 • If the learner says BREAK the intermolecular forces then MAX ⅔ (3) [9] 3

Downloaded from hlayiso.com 11102/24 QUESTION 4 4.1 4.1.1 Saturated.  It is a hydrocarbon with only single (covalent) bonds between the carbon atoms.  OR Saturated. It is hydrocarbons that have no multiple bonds between the carbon atoms. (2) 4.1.2 4.1.2.1 Addition  OR Hydrogenation (1) 4.1.2.2 Substitution  OR Hydrolysis (1) 4.1.3 Marking criteria: • Structural formula of Butene  • Structural formula of Hydrogen bromide  • Structural formula of 2-Bromobutane  • If the learner used molecular formula then MAX ⅔ (3) 4.1.4 No water must be present during the reaction  (1) 4.1.5 Water  (1) 4.1.6 2C4H10 + 13O2 → 8CO2 + 10H2O + Energy Marking criteria: • C4H10 + O2  • CO2 + H2O + (E)  • Balancing  (3) 4.1.7 Combustion OR Oxidation  (1) 4.2 4.2.1 Semiconductor  OR Metalloid (1) 4.2.2 Doping  (1) 4.2.3 n-type  (1) 4.2.4 Reverse bias  (1) 4.3 Increase  (1) [18] 4

Downloaded from hlayiso.com 11102/24 QUESTION 5 5.1 A solution/liquid/dissolved substance that conducts electricity through the movement of ions.  (0 or 2) (2) 5.2 Non-spontaneous (1) 5.3 Power Source/Battery/(Accept) Energy is added (1) 5.4 Power or source Must be negative left and positive right. (2) 5.5 NO3- (1) 5.6 Sn2++ 2e- → Sn  Marking criteria: • Sn ← Sn2++ 2e- (2/2) • Sn2++ 2e- ⇋ Sn (1/2) • Sn2++ 2e- ← Sn (0/2) NOTE: • Do not penalise if the phases are not included or an electron charge is omitted. • Penalise 1 mark if the charge on the tin ion is omitted. (2) 5.7 The rate of oxidation is equal to the rate of reduction.  OR Tin dissolves into tin ions so it is not used up (1) [10] QUESTION 6 6.1 A substance that is reduced/gains electrons (0 or 2 marks) OR A substance that undergoes reduction. (2) 6.2 Pb2+ and Zn2+  (Must list both) (1) 6.3 Temperature 25 oC/298K, (Initial) Concentration = 1mol.dm-3 (1) 6.4 To complete the circuit /To maintain (electrical) neutrality through the movement of ions (1) 5

Downloaded from hlayiso.com 11102/24 6.5 Zn + Pb2+ → Zn2+ + Pb Marking criteria: • Reactants  • Products  • Balancing  (3) 6.6 𝐸𝐸 𝜃𝜃 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 = 𝐸𝐸 𝜃𝜃 𝑐𝑐𝑐𝑐𝑐𝑐ℎ𝑜𝑜𝑜𝑜𝑜𝑜 − 𝐸𝐸 𝜃𝜃 𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎  𝐸𝐸 𝜃𝜃 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 = −0,13 − (−0,76) 𝐸𝐸 𝜃𝜃 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 = 0,63 𝑉𝑉  Marking criteria: • Positive marking from QUESTION 6.5 MAX 3/4 • No unit for the emf -1 mark NOTE: • Any other formula using unconventional abbreviations, e.g., Ecell = EOA – ERA, followed by correct substitutions: Max 3/4 (4) 6.7 V = 0(V), the circuit will be incomplete  (2) [14] TOTAL: 75 6