Physical Sciences Grade 10 P2 National Exemplar 2012 Memo

Downloaded from hlayiso.com - NATIONAL SENIOR CERTIFICATE NASIONALE SENIOR SERTIFIKAAT GRADE/GRAAD 10 PHYSICAL SCIENCES: CHEMISTRY (P2) FISIESE WETENSKAPPE: CHEMIE (V2) EXEMPLAR/MODEL 2012 MEMORANDUM MARKS/PUNTE: 150 This memorandum consists of 10 pages. Hierdie memorandum bestaan uit 10 bladsye. Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P1/Fisiese Wetenskappe V1 2 DBE/2012 NSC/NSS – Grade 10 Exemplar/Graad 10 Model – Memorandum QUESTION 1/VRAAG 1 1.1 C  (2) 1.2 C  (2) 1.3 A  (2) 1.4 D  (2) 1.5 B  (2) 1.6 A  (2) 1.7 B  (2) 1.8 A  (2) 1.9 C  (2) 1.10 D  (2) [20] QUESTION 2/VRAAG 2 2.1 2.1.1 F (1) 2.1.2 G (1) 2.1.3 E (1) 2.1.4 B (1) 2.1.5 A (1) 2.1.6 C (1) 2.1.7 D (1) 2.2 Phase change (directly) from solid to gas.  Faseverandering (direk)van vaste stof na gas.  (2) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P1/Fisiese Wetenskappe V1 3 DBE/2012 NSC/NSS – Grade 10 Exemplar/Graad 10 Model – Memorandum 2.3 Due to the higher temperature outside: Particles have higher average kinetic energy./Particles vibrate (move) faster.  Forces of attraction (between molecules) become weaker.  Regular pattern (structure) breaks down./Phase change starts to occur.  Weens die hoër temperatuur buite: Deeltjies het hoër gemiddelde kinetiese energie./Deeltjies vibreer vinniger.  Aantrekkingskragte (tussen molekule) word swakker.  Reëlmatige patroon (struktuur) word afgebreek. /Fasever-andering begin plaasvind.  (3) [12] QUESTION 3/VRAAG 3 3.1 3.1.1 54 °C  (1) 3.1.2 93 °C  (1) 3.2 No  Melting point is not 0 °C./Boiling point is below 100 °C.  Nee  Smeltpunt is nie 0 °C nie./Kookpunt is minder as 100 °C.  (2) 3.3 3.3.1 Liquid and gas  (2) Vloeistof en gas  3.3.2 Solid/Vaste stof  (1) 3.4 Remains constant.  Energy is used to break bonds during the phase change.  No energy available to increase kinetic energy of particles.  Bly konstant  Energie word gebruik om bindings te breek tydens die faseverandering.  Geen energie is beskikbaar om die kinetiese energie van deeltjies te verhoog nie.  (3) [10] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P1/Fisiese Wetenskappe V1 4 DBE/2012 NSC/NSS – Grade 10 Exemplar/Graad 10 Model – Memorandum QUESTION 4/VRAAG 4 4.1 4.1.1 Table salt/Tafelsout  (1) 4.1.2 NaCℓ  (1) 4.2 4.2.1 3px 3py 3pz n=3 3s 2px 2py 2pz n=2 2s n=1 1s Criteria for Aufbau diagram:/Riglyne vir Aufbau-diagram: Two paired electrons shown in block/circle as opposite pointing arrows in 1st energy level.  Twee gepaarde elektrone in blokkie/sirkel, as pyltjies wat in teenoorgestelde rigting wys, in die 1ste energievlak aangetoon. Eight paired electrons shown in 4 blocks/circles as opposite pointing arrows in 2nd energy level.  Agt gepaarde elektrone in 4 blokkies/sirkels, as pyltjies wat in teenoorgestelde rigting wys, in die 2de energievlak aangetoon. Six paired electrons shown in 3 blocks/circles as opposite pointing arrows and one unpaired electron shown as arrow in 3rd energy level. Ses gepaarde elektrone in 3 blokkies/sirkels, as pyltjies wat in teenoorgestelde  rigting wys, en een ongepaarde elektron in blokkie in die 3de energievlak aangetoon. (3) 4.2.2 7 (1) 4.3 4.3.1 1s22s2sp6 3s1  (2) 4.3.2 11  (1) 4.4 Na• → Na+ + e-  ●● - ●● - ● ● ● ● ● Cℓ ●● +e ● Cℓ ●● ●  ●● - ●● - Na+ + ● ● Cℓ ●● ● ● Na+ ●● Cℓ ●● ● ●  (4) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P1/Fisiese Wetenskappe V1 5 DBE/2012 NSC/NSS – Grade 10 Exemplar/Graad 10 Model – Memorandum 4.5 Ionic (lattice)  Ioniese (rooster)  (1) 4.6 4.6.1 A group of two or more atoms bonded covalently  and that behave as a unit in chemical reactions.  'n Groep van twee of meer atome wat kovalent gebind is  en wat as 'n eenheid in chemiese reaksies optree.  (2) 4.6.2 Covalent bond/Kovalente binding  (1) 4.6.3 ● ●● ● ●● ● Criteria/Riglyne: Cℓ ● Cℓ ●  ● ●● ●● • Symbols of two chlorine atoms shown with two electrons shown as dots/crosses between them.  Simbole van twee chlooratome getoon met twee elektrone aangedui as kolle/kruise tussen hulle.  • Another 6 electrons as pairs placed around each chlorine atom.  6 ander elektrone as pare rondom elke chlooratoom geplaas.  (2) [19] QUESTION 5/VRAAG 5 5.1 5.1.1 S (1) 5.1.2 S (1) 5.1.3 Q (1) 5.2 5.2.1 Q&Y (2) 5.2.2 (Group/Groep) 1  (1) 5.3 5.3.1 R (1) 5.3.2 Brick-red/Yellow-red  Baksteenrooi/Geelrooi  (1) 5.4 5.4.1 Q2P  Accept/Aanvaar: Li 2 S (1) 5.4.2 RT 2  Accept/Aanvaar: CaCℓ 2 (1) 5.5 37 17 Cℓ  Criteria/Riglyne: Correctly identified as Cℓ /Korrek as Cℓ geïdentifiseer  A = 37  Z = 17  (3) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P1/Fisiese Wetenskappe V1 6 DBE/2012 NSC/NSS – Grade 10 Exemplar/Graad 10 Model – Memorandum 5.6 5.6.1 Atoms of the same element/Atoms with the same atomic numbers, but  different mass numbers (due to difference in number of neutrons).  (2) Atome van dieselfde element/Atome met dieselfde atoomgetal, maar  verskillende massagetalle (as gevolg van 'n verskil in die aantal neutrone.)    5.6.2 5(23) + 15(25) Relative atomic mass/Relatiewe atoommassa = 20 = 24,5  (4) [19] QUESTION 6/VRAAG 6 6.1 6.1.1 (ii)  (1) 6.1.2 (i)  (1) 6.2 Gaseous phase/Gas  Gasfase/Gas  (1) 6.3 CaCO 3 (s) → CaO(s) + CO 2 (g)  Bal.  Phases/fases  Reactants  Products  Balancing  Phases  Reaktanse  Produkte  Balansering  Fases  (4) 6.4 2SO 2 (g) + O 2 (g) → SO 3 (g)  (1) 6.5 Law of conservation of mass  Wet van behoud van massa  (1) 6.6 Reactants/Reaktanse: m(2SO 2 ) + m(O 2 ) = 2(32 + 32) + 32 = 128 + 32 = 160 g  Products/Produkte: m(2SO 3 ) = 2(32 + 48) = 160 g  Mass(reactants) = mass(products)  Massa(reaktanse) = massa(produkte)  (3) [12] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P1/Fisiese Wetenskappe V1 7 DBE/2012 NSC/NSS – Grade 10 Exemplar/Graad 10 Model – Memorandum QUESTION 7/VRAAG 7 7.1 7.1.1 No free/mobile ions.  Geen vrye/beweeglike ione nie.  (1) 7.1.2 Electrolyte/Elektroliet  (1) 7.1.3 NH+4  & NO3−  (2) 7.1.4 OPTION 1/OPSIE 1 OPTION 2/OPSIE 2 m m n(NH 4 NO 3 ) =  c((NH 4 NO 3 ) =  M MV 15 15 =  =  80 (80)(250 × 10 − 3 ) = 0,19 mol = 0,75 mol∙dm-3  n c(NH 4 NO 3 ) =  V 0,19 =  250 × 10 − 3 = 0,75 mol∙dm-3  (5) 7.2 7.2.1 Barium sulphate/Bariumsulfaat  BaSO 4  (2) 7.2.2 To ensure the precipitate is indeed a sulphate./Barium sulphate is insoluble in nitric acid.  Om te bevestig dat die presipitaat wel 'n sulfaat is./Bariumsulfaat is onoplosbaar in salpetersuur.  (1) 7.2.3 B  (2) 7.3 7.3.1 BaCℓ 2 (aq) + MgSO 4 (aq) → BaSO 4 (s)+ MgCℓ 2 (aq)  Bal.  Phases:  Reactants  Products  Balancing  Phases  Reaktanse  Produkte  Balansering  Fases  (4) 7.3.2 Precipitation reaction/Presipitasiereaksie  (1) [19] Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P1/Fisiese Wetenskappe V1 8 DBE/2012 NSC/NSS – Grade 10 Exemplar/Graad 10 Model – Memorandum QUESTION 8/VRAAG 8 8.1 8.1.1 m n(Mg) = M 1,5 =  24 = 0,0625 mol n(H 2 ) = n(Mg) = 0,0625 mol   Any one/Enige een m(H 2 ) = nM = (0,625) (2) = 0,125 g  (5) 8.1.2 POSITIVE MARKING FROM QUESTION 8.1.1 POSITIEWE NASIEN VAN VRAAG 8.1.1 V n(H 2 ) =  V m V 0,0625 =  22,4 ∴ V = 1,4 dm3  (3) 8.1.3 POSITIVE MARKING FROM QUESTION 8.1.1 POSITIEWE NASIEN VAN VRAAG 8.1.1 m n(MgCℓ 2 ) =  M m 0,0625  =  95 ∴ m = 5,94 g  (4) 8.1.4 POSITIVE MARKING FROM QUESTION 8.1.1 POSITIEWE NASIEN VAN VRAAG 8.1.1 N n(Cℓ) =  N A N 2(0,0625)  =  6,02 × 1023 ∴ N(Cℓ atoms/atome) = 7,53 x 1022  (3) 8.2 M(Na 2 CO 3 ) = 106 g∙mol-1  M(xH 2 O) = 268 – 106 = 162 g∙mol-1  162 n(H 2 O) =  = 9 mol  18 (4) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P1/Fisiese Wetenskappe V1 9 DBE/2012 NSC/NSS – Grade 10 Exemplar/Graad 10 Model – Memorandum 8.3 8.3.1 The formula which gives the simplest whole-number ratio of atoms in the compound.  Die formule wat die eenvoudigste heelgetalverhouding van atome in die verbinding voorstel.  (2) 8.3.2 In 100 g of compound/In 100 g van die verbinding: 71,65g Cℓ; 24,27 g C and 4,07 g H 71,65 n(Cℓ) = = 2,02 mol  35,5 24,27 n(C) = = 2,02 mol  12 4,07 n(H) = = 4,07 mol  1 Whole number ratio/Heelgetalverhouding: 2,02 2,02 4,07 : :  2,02 2,02 2,02 C : H : Cℓ = 1 : 2 : 1 (5) Empirical formula/Empiriese formule = CH 2 Cℓ  [26] QUESTION 9/VRAAG 9 9.1 9.1.1 Evaporation/Verdamping  (1) 9.1.2 Condensation/Kondensasie  (1) 9.1.3 Transpiration/Transpirasie  (1) 9.2 9.2.1 (Sample/Monster) 1  Too acidic/Té suur  (2) 9.2.2 SO 2 + H 2 O  → H 2 SO 3  Bal.  Reactants  Products  Balancing  Reaktanse  Produkte  Balansering  (3) 9.2.3 ANY ONE/ENIGE EEN: • Destroy/Damage/Harm plants.  Vernietig/Beskadig plante.  • Less food for animals due to damage to plants/crops. Minder voedsel vir diere as gevolg van skade aan plante/gewasse. (1) Copyright reserved/Kopiereg voorbehou Please turn over/Blaai om asseblief

Downloaded from hlayiso.com Physical Sciences P1/Fisiese Wetenskappe V1 10 DBE/2012 NSC/NSS – Grade 10 Exemplar/Graad 10 Model – Memorandum 9.3 9.3.1 ANY ONE/ENIGE EEN: • Disinfectant/Ontsmettingsmiddel  • Destroy harmful bacteria/organisms Vernietig skadelike bakterieë/organismes (2) 9.3.2 AgNO 3 /Silver nitrate/Silwernitraat  (2) [13] TOTAL/TOTAAL: 150 Copyright reserved/Kopiereg voorbehou