Technical Sciences PAT Marking Guidelines English

Downloaded from hlayiso.com Ss e e “—™2e basic education (/ SE \) Department: \¥ ¥ . . EN 7" Basic Education >> ZS REPUBLIC OF SOUTH AFRICA TECHNICAL SCIENCES PRACTICAL ASSESSMENT TASKS GRADE 12 2018 MARKING GUIDELINES These marking guidelines consist of 19 pages. Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences 2 DBE/PAT 2018 NSC — Grade 12 ~ Marking Guidelines GRADE 12 FORMAL EXPERIMENTS EXPERIMENT 1: DETERMINE THE RELATIONSHIP BETWEEN ACCELERATION AND FORCE FOR A CONSTANT MASS. WORKSHEET FOR NEWTON'S SECOND LAW: OPTION 1 35 PRACTICAL SKILLS 1. Following instructions and manipulation. CRITERIA MARKS Accurately following a sequence | Following a sequence of instructions of written/verbal instructions including branched instructions Manipulative skills include | Able to use all apparatus and material correct and safe handling of correctly and safely 4 apparatus and materials 2.1 Dependent variable: Acceleration” (1) 2.2 Independent variable: Net force” (1) 2.3 Controlled variable: Mass of the system (mass of the trolley and mass pieces)” Accept: Angle of inclination of the surface. OR surface OR length of the runway. (1) 3. NOTE: Credit 4 marks for free body diagram ONLY. The reason for raising the runway MUST be credited on subquestion 4. This question should have read as follows: In point 1 of the METHOD of the experiment, you were asked to raise the runway. Draw a fully labelled free body diagram showing ALL forces acting on the trolley placed on the raised runway. OPTION 1: Normal force N (Accept: = = Reaction force R Marking Criteria: Frictional force f Normal force” Frictional force” Fapplied Es, Fos Weight (2 components)” Credit: Weight/Gravitational for F, | Faretes (tension on the string)” NOTE: If only ONE of the components is incorrect: No mark. (4) Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences 3 DBE/PAT 2018 NSC — Grade 12 — Marking Guidelines OPTION 2: Normal force N (Accept: Reaction force R) 7 Frictional force f Fappiied F Credit: Weight/gravitational for F, NOTE: For both OPTION 1 & 2 credit if the frictional, normal and applied forces are facing the other way indicated in the diagram below: Frictional force, f Normal force N (or reaction force R) NS F, a Fa, YF soptied 4. To overcome (the effects of) friction.” (1) NOTE: Allocate ONE mark, not two marks as indicated in the questions. 5. To keep the mass of the system (mass of the trolley and mass pieces) constant” (1) NOTE: Allocate ONE mark, not two marks as indicated in the questions. 6. Data representation and interpretation of results TABLE 1: 1_mass piece (10 g) hanging (18) Interval Mass | Time _ _ fT i = Ax (kg) (s) AVE Vr; =a Free=ma 98 4,45 )| 0,146-0=) | 0146 0,0263 1 0,65 | 0,7! 0,146 A45, 4,45 =0,033 | 4.50 0,144 ~0ov > 0,144 0,0255 } , — v 2 0,65 | 0,798 | 7 ='0,144 450 =9,032v 4,49 0,145 -05) 0,146 0,0263 3 0,65 | 0,798 0145 445 =0.033 Average | 0,65 | 0,798 | 4,48 0,145 0,033 0,0260 Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences 4 DBE/PAT 2018 NSC — Grade 12 — Marking Guidelines j mass pieces (2 x 10 g) hanging Interval Mass | Time _ VeVi - 4x | kg) | fs) | Sv= Yew =“ Fema 1 aes iio 2,48 0,262 - 0 0,262 0,0835 , , 788 = 0,262 48 2.48 =0,106 2,45 »| 0,265-0 > 0,265 0,0851 , , —— v 2 | 0,65) 0,788) “Y () O s65v 2.45 <0 1087 2,54)| 0,256-0 )| 0.256 0,0796 3 | 0,65 | 0,788 = 0,256 | 254 ~ 104 Average | 0,65 | 0,788 | 2,49 0,261 0,105 0,0827 3 mass pieces (3 x 10 g) hanging Interval Mass | Time - _ pai = Ax (kg) (s) Av=VrFV; a= ir Fretma 1,70 ) | 0,382-0 0,382 0,175 1 0,65 | 0,778 = 0,38 170 J =0,225 1,78 $|0,365-0 || 0,365 0,158 2 0,65 | 0,778 | / ='0,365"" 178 <9 295v v - 0,365 0,159 3 | 0,65) 0,778 | 178 } | 9.3650 | | “<> | = 0,365 178 =0,205 | Average | 0,65 | 0,778 | 1,75 0,371 0,211 0,164 4 mass pieces (4 x 10 g) hanging Interval Ax ea) ie Av= vey; a= “ Fref=ma 1,51 )/0,430-0 \/ 0433. 0,220 ) | 1 0,65 | 0,768 = 0,430 “451 191 =0,287 1,51 ‘| 0,430-ov || 0,433 0,220 2 | 0,65 | 0,768 | 7 ='0,430 151 0.2870 v 1,51 ||0,430-0 || 0.433 9,220 3 0,65 | 0,768 = 0,430 151 =0,287 Average | 0,65 | 0,768 | 1,51 0,430 0,287 0,220 NOTE: Mass indicated in all 4 tables” Ax indicated in all 4 tables ¥ Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences 5 DBE/PAT 2018 NSC — Grade 12 — Marking Guidelines 2 mass pieces (2 x 10 g) hanging | Interval Mass | Time = _ Up~ i = Ax (kg) (s) Av=Vrvi a=— Fre=ma Bes eee 2,48 0,262- 0 0,262 0,0835 1 5 788 = 0,262 >3aR- 2,48 -0 106 2,45») 0,265-0 7} 9,265 0.0851} ’ : ee v 2 | 0.65 | 0,788) “Y (Oo seey |) a5 “0,108 - 0,256 0,0796 3 | 0,65 | 0,788 | 7°4/) 0256-0 Er =0, 254 =0 101 Average | 0,65 | 0,788 | 2,49 0,261 0,105 0,0827 3 mass pieces (3 x 10 g) hanging Interval Mass | Time _ : _ UF Yj = Ax (kg) (s) Av = VV; a= i F,ee=ma 1,70 ) | 0,382-0 0,382 0,175 1 0,65 | 0,778 = 0,38 zn 170 =0,225 1,78 0,365-0 0,365 0,159 2 | 0,65/ 0,778 | 2 =0,365 [| 178 <9 o06v v 1,78 || 0,365-0 | | 0365 9,158 3 0,65 | 0,778 | ° _ WR = 0,365 178 -9 205 Average | 0,65 | 0,778 1,75 | 0,371 0,211 0,164 4 mass pieces (4 x 10 g) hanging Interval Mass | Time =v. ad a = Ax (kg) (s} AVE VFV; a= he Fret=ma 1,51 )| 0,430-0 0,433 0,220 1 0,65 | 0,768 = 0,430 Ti 151 =0,287 1,51 \\ 0,430- ov =| 0.433 0,220 } ’ = v | 2 | 0,85 | 0,768 | 7 0.430 151 <o287v | 7 0,433 0,220 3 | 0,65 | 0,768 | 157 }| 9430-0 |) —=Se | = 0,430 181 =0,287 | Average | 0,65 | 0,768 | 1,51 | 0,430 0,287 0,220 NOTE: Mass indicated in all 4 tables” Ax indicated in all 4 tables ¥ Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences 6 DBE/PAT 2018 NSC - Grade 12 — Marking Guidelines 2 mass pieces (2 x 10 g) hanging Interval Mass | Time =v.y. _ Uri = Ax (kg) (s) AVE VPV; a= i Free=ma 1 2,48 0,262- 0 0,262 0,0835 0,65 | 0,788 = 0,262 DAg- 2,48 =o 106 2 0,65 0788 2,45 0,265-0 0,265 i v = 0,265¥ 2,45 =0,108” 3 0,65 o7ag| 254) 0,256-0) | 0,256 0,0796 | , = 0,256 2,54 =0,101 Average | 0,65 | 0,788 | 2,49 0,261 ‘| 0,105 3 mass pieces (3 x 10 g) hanging — Interval Mass | Time _ _ Ue = Ax (kg) (s) Av = Vr-Vi a= ie) Fre=ma 4 oes llo778 1,70 | | 0,382-0 0,382 1 A = 0,38 170 =9,225 2 0.65 | 7g | 1,78 | 0.365-0 || 0,365 “| £9,865 | | 478 <0 205v 3 0,65 0,778 1,78 0,365 -0 0,365 , = 0,365 1,78 =0,205 Average | 0,65 | 0,778 | 1,75 0,371 0,211 4 mass pieces (4 x 10 g) hanging Interval Mass | Time _ _ URTV - Ax (kg) (s) AVE VFVi a= “i F,¢=mMa 1 1,51 0,430- 0 0,433 0,65 | 0,768 = 0,430 “451 . =0,287 2 1085 | neg | 1:51} 0.430- ov =) 0,433 ees 0,430 151-9 287v 5/065 | reg | 151 | 0430-0 || 0.433 ‘ =0, 30 151 =0,287 Average | 0,65 | 0,768 | 1,51 0,430 0,287 NOTE: Mass indicated in all 4 tables” Ax indicated in all 4 tables Vv Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences 7 DBE/PAT 2018 NSC — Grade 12 — Marking Guidelines Ts Data analysis A graph of Fret Vs acceleration. 030 0.25 0.20 s O45 & 005 ~o,io ~ oas “920 77" 0.25 0.30 Fea (N) MARKING CRITERIA Heading indicated v Axis labelled with correct units v 4 points plotted v A straight-line graph drawn v | Total 4 marks (4) 8. Conclusion Acceleration is directly proportional to the net force” provided the mass remains constantY - (2) TOTAL: 35 Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences 8 NSC - Grade 12 ~ Marking Guidelines DBE/PAT 2018 THE RELATIONSHIP BETWEEN RESULTANT FORCE AND ACCELERATION (NEWTON'S SECOND LAW) WORKSHEET FOR NEWTON'S SECOND LAW: OPTION 2 35 PRACTICAL SKILLS 1. Following instructions and manipulation. CRITERIA. MARKS Accurately following a sequence of | Following a sequence of 4 written/verbal instructions instructions including branched instructions _| Manipulative skills include correct | Able to use all apparatus and 1 and safe handling of apparatus and | material correctly and safely materials 2.1 Dependent variable: Acceleration” (1) 2.2 Independent variable: Net force” (1) 2.3 Controlled variable: Mass of the system (trolley and mass pieces)” Accept: Angle of inclination of the surface. OR surface OR length of the runway. (1) 3. 4 T=f a T= 50yv T= 0,02 sv (2) 4. t=nxT t= 10x 0,02v t=0,2sv (2) 5. e Using an extensible string “~ Not compensating for friction Failure to ensure that there is no friction or little friction between pulleys Any and the thread. one ¢ Failure to switch off the fan so that the wind does not affect the results. (1) Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences 9 NSC — Grade 12 - Marking Guidelines 6. Make sure that the runway is firmly secured.“ Handle elastic/rubber bands with care to avoid hitting other learners. ¢ Do not use/touch bare electrical conductors when they are being used.| one ¢ Avoid loose cables on floor so that learners do not trip over them (use tape to fix them to the floor). DBE/PAT 2018 Any 7. TABLE 1: Using 1 rubber band Trial | Resultant | PQ (m) Vx QR vy a F Fret number | force, F (m-s") (m) (m-s’ | (ms?) | ‘net (N) (number ' a of elastic ki bands) - (ka) __ | 1 1 0,019) | 0,095) | 0,042) 0,21 }| 0,575) | 0,758 | 0,436 ) 2 1 0,018| | 0,090 0,044 | 0,22 {0,650 [| 0,758 | 0,493 | 3 1 0,020 0,100 0,038 0,19 0,450 0,758 | 0,341¥] Average 1 0,019" 0,095 0,041 0,217) 0,558 0,758 | 0,423 J | Fret NOTE: 4 =m =0,758 kg (mass of a trolley) but Free =ma Using 2 rubber bands - Trial | Resultant | PQ (m) Vx QR vy a FE Fret number | force, F (m-s") | (m)_ | (m-s*) | (m-s*) | [het | (N) (number a of elastic g bands) (ka) 1 2 | 0,037) | 0,185 } | 0,069 }| 0.345% | 0,800 ) | 0,758 | 0,606) 2 2 0,039 0,195 0,071 it 0,355 0,800) 0,758 | 0,606 | | 3 2 0,038 0,190 0,073 I 0,365 0,875 0,758 | 0,663 Average 2 0,038” | 0,190 | 0,062 | 0,355/ | 0,825 J 0,758 | 0,625 Using 3 rubber bands Trial Resultant | PQ (m) Vy QR Vy a FE Foret number | force, F (m-s*) | (m) | (m-s*) | (m-s?) | [net (N) (number a of elastic k _ bands) __it : (ks) _ 1 3 0,055) | 0,275 || 0,096) | 0,480 | 1,025 ]| 0,758 | 0,777) | 2 3 0,049) | 0,245 b{ 0,093 | 0.4657 1,10 0,758 | 0,834 3. | 3 0,053] | 0,265 || 0,095 | 0.475| | 1,050 || 0,758 | 0,796 Average 3 0,052 | 0,262” | 0,095” | 0,4737 | 1,058” | 0,758 | 0,802% Copyright reserved (1) (18) Please turn over

Downloaded from hlayiso.com Technical Sciences 10 DBE/PAT 2018 NSC — Grade 12 - Marking Guidelines 8. Data analysis Draw a graph of Fret vs acceleration. (4) Acceleration versus Free graph Acceleration inms? 2 + 0,2 — — ~ _ ° - —_— a 0,2 0,4 06 og 1 Fret inN OR a graph of acceleration versus Fy. a Lo r ne Ber rs t Oy - toe B2 C4 Ce 68 Free tu) MARKING CRITERIA Heading indicated v Axis labelled with correct units v 4 points plotted v A straight-line graph drawn v Total 4 marks 9. Conclusion Acceleration is directly proportional to the net force” provided the mass remains constant¥ (2) TOTAL: 35 Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences 11 NSC - Grade 12 — Marking Guidelines DBE/PAT 2018 THE RELATIONSHIP BETWEEN RESULTANT FORCE AND ACCELERATION (NEWTON'S SECOND LAW) WORKSHEET FOR NEWTON'S SECOND LAW: OPTION 3 PRACTICAL SKILLS 1. 2.1 2.2 2.3 Following instructions and manipulation. 35 materials CRITERIA MARKS Accurately following a sequence of | Following a sequence of instructions (1) written/verbal instructions. including branched instructions Manipulative skills include correct | Able to use all apparatus and and safe handling of apparatus and | material correctly and safely. (1) Dependent variable: Acceleration” Independent variable: Net force” Controlled variable: Mass of the system (Mass of the trolley and mass pieces)” Accept: Angle of inclination of the surface. OR surface OR length of the runway. 1 tTz=fv 1 T= 50v T=0,02s t=nxT t=10x0,02V t=0,2 sv « Using an extensible string.” e Not compensating for friction Failure to ensure that there is no friction or little friction between pulleys and the thread. e Failure to switch of the fan so that the wind does not affect the results. Copyright reserved Any one (1) (1) (1) (2) (2) (1) Please turn over

Downloaded from hlayiso.com Technical Sciences 12 DBE/PAT 2018 NSC — Grade 12 — Marking Guidelines 6. e Switch off all electrical appliances when not in use.” Make sure that the runway is firmly secured. Do not use/touch bare electrical conductors when they are being used | Any by anyone. one e Avoid loose cables on floor so that learners do not trip over them (use tape to fix them to the floor). (1) 7. TABLE 1: 20 g mass piece (2 x 10 g) hanging and 40 g stacked on top of the trolley Trial | Resultant) Distance | vx (ms') | Distance | v,(ms") | a(ms”) Number force: PQ (m) QR (m) (Fr =Fg = mg) 1 (0,196 (0,038 (0,190 0,084) (0,420) ita 2 0,196] 0,039¥ (0,195¥ (0,088; (0,440) 14,2257 3 10,196 (0,037 0,185 (0,084 0,420 1,179 Average (0,196 0,038 0,190 (0,085 0,427) 1,183 NOTE: 20g = 0,02 kg and Period (T) of the time is 0,02 s but in each interval PQ and QRt=0,2s. 40 g mass piece (4 x 10 g) hanging and 20 g stacked on top of the trolley Trial | Resultant] Distance | v,(ms')| Distance | v,(ms') | a(ms”) | Number force: PQ (m) QR (m) (Fr =Fg = mg) 1 (0,392 0,074 0,370) (0,138 0,690 1,600 2 0,392 00,0734 0,365) 0,136 0,680 1,5754 3 (0,392 0,077 0,385 (0,136 0,680 1,475 Average (0,392 0,075 0,375 0,137 0,683 1,559 60 g mass piece (6 x 10 g) hanging and no mass stacked on top of the trolley Trial | Resultant] Distance | v,(ms') | Distance | v,(ms") | a(ms”) Number force: PQ (m) QR (m) (Fr =Fg = mg) 1 (0,588 0,110 0,550 (0,192 0,960) 2,050 2 (0,588) 0,107 0,535Y 0196/ [o,980¥ 2.2254 — 3 (0,588 0,107| 0,535] o,194/ 0,970) 175] | Average (0,588 0,108 0,540 0,194 0,970 P1580, Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences 13 DBE/PAT 2018 NSC — Grade 12 — Marking Guidelines 8. Data analysis Acceleration versus F(net)/resultant force. 25 7— nN a wu Acceleration in m.s-2 b | | | s uw | | | ° oO ol 0,2 0,3 O4 0,5 0.6 OF Fret in N MARKING CRITERIA Heading indicated v Axis labelled with correct units v 4 points plotted v A straight-line graph drawn v Total 4 marks (4) 9. Conclusion Acceleration is directly proportional to the net force” provided the mass remains constant” (2) TOTAL: 35 Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences EXPERIMENT 2: DETERMINE THE PATH OF A RAY OF LIGHT THROUGH A GLASS 14 DBE/PAT 2018 NSC — Grade 12 — Marking Guidelines SLAB FOR DIFFERENT ANGLES OFINCIDENCE. WORKSHEET FOR EXPERIMENT 2 PRACTICAL SKILLS 1. Following instruction and manipulation. 35 materials CRITERIA MARKS Accurately following a sequence of | Following a sequence of written/verbal instructions. instructions including branched 1 instructions Manipulative skills include correct | Able to use all apparatus and and safe handling of apparatus and | material correctly and safely. 1 2.1 Dependent variable: Angle of refraction” 2.2 Independent variable: Angle of incidence ¥ 2.3. Controlled variable: Frequency/wavelength of light OR Rectangular glass block” 3. Incorrect measurement of the angle of incidence and the angle of refraction.” 4. Do not point a laser beam/light ray at another learner's eyes. OR Switch off all electrical appliances when they are not being used. OR Do not use/touch bare electrical conductors when they are being used. 5. TABLE 1: Experiment | Angle of Angle of | Angle ofemergence | incidence refraction (degrees) (degrees) (degrees) | 1 70¥ 38,87 70¥ 2 60” 35,3 60v 3 50v 30,7¥ 50” | Any four sets 4 40v 254% =| 40v 5 30 19,5 30 6 20 13,2 20. | Copyright reserved (1) (1) (1) (1) (1) (12) Please turn over

Downloaded from hlayiso.com Technical Sciences 15 DBE/PAT 2018 NSC ~ Grade 12 — Marking Guidelines 6.1 A labelled ray diagram. E N Q A B ~ F vr : ~ N ~ i a t 1G i - 1 iB) re Cc i ‘ . H CRITERIA MARK Measuring the incident angle correctly 1 Measuring the angle of refraction correctly 1 Drawing the line GF 1 Drawing the line GH 1 | Measuring the emergent angle correctly 1 | TOTAL - § (5) 6.2 The angle of incidence is greater than the angle of refraction. ”” (2) 6.3. The angle of incidence is smaller than the angle of refraction’ (because light is moving from a medium of higher optical density, glass, to a medium of lower density, air). (2) 6.4 Air has a refractive index of 1,00’ which is a lower than refractive index glass, which is 1,5.” OR Glass has higher optical density than air. (2) 6.5 When the light ray moves from the air to the glass, the light ray bends towards the normal. “ When the light ray moves from the glass block back into the air, it bends away from the normal v (and the angle of emergence is larger the incident angle between glass and air). (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Technical Sciences 16 DBE/PAT 2018 NSC — Grade 12 — Marking Guidelines 6.6 The direction of the light ray through different media. ae L NOTE: This subquestion MUST be disregarded and this experiment must be marked out of 34 instead of 35 marks. 7. Conciusion If light enters any substance with a higher refractive index (such as from air into glass) it slows down. The light bends towards the normal line.” OR If light enters a substance with a lower refractive index (such as from water into air) it speeds up. The light bends away from the normal line. OR A higher refractive index shows that light will slow down and change direction more as it enters the substance. (2) TOTAL: 34 Copyright reserved Please turn over

Technical Sciences 2.1 2.2 2.3 Copyright reserved EXPERIMENT 3: WORKSHEET FOR EXPERIMENT 3 PRACTICAL SKILLS Downloaded from hlayiso.com 17 DBE/PAT 2018 NSC — Grade 12 ~ Marking Guidelines TO DETERMINE THE ELECTRODE POTENTIAL OF A Cu-Zn ELECTROCHEMICAL CELL. 35 Following instruction and manipulation. | CRITERIA | | MARKS | Accurately following a sequence of | Following a sequence of | written/verbal instructions. instructions including branched 1 instructions Manipulative skills include correct | Able to use all apparatus and and safe handling of apparatus and | material correctly and safely 1 (1) Dependent variable: Emf” (voltmeter reading) Independent variable: Type of electrolyte and electrodes usedY (1) Controlled variable. Type of voltmeter” Length of the connecting wires with crocodile clippers Any one Temperature (of the electrolyte solution) salt bridge solution (1) Temperature and concentration not under standard conditions” Voltmeter readings errors Any Salt bridge solution leaking or unsuitable electrolyte used one (1) Switch off all electrical appliances when not in use.” Do not use/touch bare electrical conductors when they are being used. Any Avoid skin/eye contact with the electrolytes. one (1) Please turn over

Downloaded from hlayiso.com Technical Sciences 18 DBE/PAT 2018 5. 6.1 6.2 6.3 6.4 6.5 6.6 Copyright reserved NSC — Grade 12 — Marking Guidelines TABLE 1: Mass of Electrodes Plate/Electrode | Initial Mass | Final Mass Copper 4,329 | 6,89 g | Zinc 5,02 gf 4,25 gv} Voltmeter readings | Before placing the U-tube filled | 0 Vv’ | After placing the U-tube 1,1 VY with a salt solution/paste in the filled with a salt solution/ beakers paste in the beakers Colours of the electrodes At the beginning of the Between10 to 20 minutes experiment during the reaction Copper electrode Brown copper colour” Brown copper colour” Zinc Electrode | Shiny metallic colourY _| Dull metallic colour” Colours of the solutions in the beakers At the beginning of the A few hours after the reaction | reaction occurred CuSO, Blue solution” Colourless/Light blue ___| solution” ZnSO, Colourless solution” | Colourless solution” To keep the solution of KNO; (potassium nitrate) inside the salt bridge” but allow the ions in the salt bridge to move across the cotton wool membrane. “ As the reaction proceeds, the zinc electrode oxidizes and decreases in mass because zinc atoms in the zinc electrode form zinc(II) ions.“ Simultaneously, the copper electrode gains mass, because the copper(I!) ions gain electrons to form copper metal which is deposited on the copper electrode, thus increasing its mass.v The original colour of the zinc sulphate is colourless. The Zn** ions react with the NO; ions, from the salt bridge, as the reaction proceeds and the colour of the electrolyte remains colourless.” The blue copper sulphate electrolyte solution changes to colourless or light blue, because the copper(II) ions form Cu atoms which are deposited on the copper electrode. ” Zinc electrode is the anode.” Copper electrode is the cathode” Cu**(aq) + 2e° — Cu(s)vv Zn(s) — Zn**(aq) + 2evv (12) (2) (2) (2) (2) (2) (2) Please turn over

Downloaded from hlayiso.com Technical Sciences 19 DBE/PAT 2018 NSC — Grade 12 — Marking Guidelines 6.7 NOTE: This subquestion MUST be disregarded and this experiment must be marked out of 33 instead of 35 marks. For the responses below the question should have read as follows: What is the importance of the U-tube filled with a salt solution that was placed between the CuSO, and ZnSO, electrolytes? e It completes the cell.” ¢ Maintain electrical neutrality (by allowing the ions to move between the two half cells)” (2) 7. Conclusion The electrode potential of the zinc-copper cell is 1,10 VY“ (2) TOTAL: 33 NOTE: The total marks for this PAT are 103 NOT 105 as indicated in the instruction booklet. Copyright reserved