PREPARATORY EXAMINATION VOORBEREIDENDE EKSAMEN GRADE/GRAAD 12 SEPTEMBER 2014

Transcription

1 PREPARATORY EXAMINATION VOORBEREIDENDE EKSAMEN GRADE/GRAAD SEPTEMBER 04 PYSICAL SCIENCES/FISIESE WETENSKAPPE PAPER/VRAESTEL (CEMISTRY/CEMIE) MARKS/PUNTE: 50 TIME/TYD: 3 OURS/UUR This eorandu consists of 3 pages. ierdie eorandu bestaan uit 3 bladsye.

2 Meo: PhySci P/Fis Wet V Gr FSDoE/VSDvO Septeber 04 QUESTION /VRAAG. B (). C ().3 C ().4 B ().5 D ().6 C ().7 A ().8 A ().9 C ().0 B () QUESTION /VRAAG... E ().. C ()..3 B ()..4 G ()..5 B & (). IF/INDIEN: Correct IUPAC nae, but one or ore of the following errors: oitting hyphens and/or coas; including extra spaces and/or hyphens Korrekte IUPAC-naa, aar een of eer van die volgende foute: weglating van koppeltekens en/of koas; insluiting van ekstra spasies en/of koppeltekens Max./Maks... 3-ethylpentanal 3-etielpentanaal ().. 4-ethylhex--yne 4-etielheks--yn OR/OF 4-ethyl--hexyne 4-etiel--heksyn ()..3,4-diethylhexane /,4-dietielheksaan ()

3 Meo: PhySci P/Fis Wet V Gr 3 FSDoE/VSDvO Septeber C C C C C Br Br Functional group Funksionele groep Whole olecule correct ele olekuul korrek.3. IF/INDIEN: Condensed or sei-structural forula: Gekondenseerde of seistruktuurforule: Molecular forula/molekulêre forule: O C C C C C C 0 Functional group Funksionele groep Whole olecule correct ele olekuul korrek () IF/INDIEN: Condensed or sei-structural forula/ Gekondenseerde of seistruktuurforule: Molecular forula/molekulêre forule: 0 ().4.4. Esterification / Verestering / Esterifikasie ().4. O C C O C C C Functional group Funksionele groep Whole olecule correct ele olekuul korrek IF/INDIEN: Condensed or sei-structural forula/ Gekondenseerde of seistruktuurforule: Molecular forula/molekulêre forule: 0 () [8]

4 Meo: PhySci P/Fis Wet V Gr 4 FSDoE/VSDvO Septeber 04 QUESTION 3/VRAAG Alkanes / Alkane () 3.. Chain (isoeris) / Ketting(isoerise) () Branching / Vertakking Note/Let wel: No arks for: nuber of C atos / chain length Geen punte vir: aantal C-atoe / kettinglengte () 3.. Structure/Stuktuur: Fro A to C/Van A na C: Branching decreases / olecules becoe less copact / surface area increases (over which interolecular forces act). Vertakking verinder / olekule word inder kopak / oppervlak (waaroor interolekulêre kragte werk) word groter. Interolecular forces/interolekulêre kragte: Stronger or ore interolecular forces / Van der Waals forces / dispersion forces / London forces. Sterker of eer interolekulêre kragte / Van der Waalskragte / dispersiekragte / Londonkragte. Energy/Energie: More energy needed to overcoe interolecular forces / Van der Waals forces / dispersion forces / London forces. Meer energie benodig o interolekulêre kragte / Van der Waalskragte / dispersiekragte / Londonkragte te oorko B Lowest boiling point / Laagste kookpunt () London forces / Dispersion forces Londonkragte / Dispersiekragte () 3.3. London forces / Dispersion forces Dipole-dipole forces Londonkragte / Dispersiekragte Dipool-dipoolkragte () 3.4 The hydrogen bonds between olecules of E are stronger than the dipole-dipole forces between olecules of D. Die waterstofbindings tussen olekule van E is sterker as die dipool-dipoolkragte tussen olekule van D. () [3]

5 Meo: PhySci P/Fis Wet V Gr 5 FSDoE/VSDvO Septeber 04 QUESTION 4/VRAAG Addition / hydration Addisie / hidrasie / hidratering () 4.. Substitution / halogenation / chloronation Substitusie / halogenasie / halogenering / chloronering () 4..3 Eliination / dehydration Eliinasie / dehidrasie / dehidratering () SO4 / 3PO4 () 4.. C C C O Functional group Funksionele groep Whole olecule correct ele olekuul korrek ACCEPT/AANVAAR:-O as condensed/ as gekondenseerd IF/INDIEN: Condensed or sei-structural forula/ Gekondenseerde of seistruktuurforule: Molecular forula/molekulêre forule: 0 () ydration / idrasie / idratering () 4.3. Marking guidelines/nasienriglyne: One ark for each correct structure./een punt vir elke korrekte struktuur. Accept olecular forula for./aanvaar olekulêre forule vir. Marking rule /Nasienreël Any additional reactants or products:/enige addisionele reaktanse of produkte: Max./Maks. 3 C C C + C C C If arrow in equation oitted:/indien pyltjie in vergelyking uitgelaat is: Max./Maks. 3 (3)

6 Meo: PhySci P/Fis Wet V Gr 6 FSDoE/VSDvO Septeber chloropropane / -chloropropaan () 4.4. Sodiu hydroxide / Potassiu hydroxide Natriuhidroksied / Kaliuhidroksied () Dilute base / Verdunde basis Mild heat / Matige hitte () [5] QUESTION 5/VRAAG 5 5. The concentration of hydrochloric acid decreases. Die konsentrasie van soutsuur verinder. () 5. Mass (g) Marking criteria/nasienriglyne Correct shape with decreasing gradient as shown./korrekte vor et afneende gradiënt soos aangetoon. Graph ends parallel to x axis and does not touch the x axis./grafiek eindig parallel aan x-as en raak nie die x-as nie. Tie (s) () 5.3 Increases / Verhoog At a higher teperature, ore olecules have enough/sufficient kinetic energy / ore olecules have kinetic energy greater than the activation energy. By 'n hoër teperatuur het eer olekule genoeg kinetiese energie / eer olekule het kinetiese energie hoër as die aktiveringsenergie. More effective collisions per unit tie/second. Meer effektiewe botsings per eenheidstyd/sekonde. (3) 5.4 Potential energy / Potensiële energie (J) (a) (c) (d) Correct shape/korrekte vor (a) & (b) as shown/soos aangetoon (c) as shown/soos aangetoon (d) as shown/ soos aangetoon (b) Course of reaction / Reaksieverloop No labels on axis/geen benoeings op asse: Max./Maks. 3 4 IF shape for endotheric reaction/indien vor vir endoteriese reaksie: 0 4 (4)

7 Meo: PhySci P/Fis Wet V Gr 7 FSDoE/VSDvO Septeber Substitution of volue and concentration of acid. Substitusie van volue en konsentrasie van suur. Using ratio/gebruik verhouding: (Mg) = ½n(Cl) Substitution of 4 in n /Substitusie van 4 in n M M Initial ass/ole Mg ass/ole Mg reacted Aanvanklike assa/ol Mg assa/ol Mg gereageer Final answer/finale antwoord: 9,6 g c = V n n = n = 0, ol n(mg reacted/gereageer) = ½n(Cl) = 0, ol OPTION /OPSIE OPTION /OPSIE (Mg reacted/gereageer): n(mg) = M 0, = 4 =,4 g (Mg) in excess/in ooraat: =,4 = 9,6 g n(mg initially/aanvanklik): n = M = 4 = 0,5 ol n(mg in excess/in ooraat): n = 0,5 0, = 0,4 ol (Mg in excess/in ooraat): n = M 0,4 = 4 = 9,6 g (5) [5]

8 Meo: PhySci P/Fis Wet V Gr 8 FSDoE/VSDvO Septeber 04 QUESTION 6 6. oogeneous / oogeen Reactants and products are in the sae phase. Reaktanse en produkte is in dieselfde fase. () 6. CALCULATIONS USING NUMBER OF MOLES: BEREKENINGE WAT GETAL MOL GEBRUIK: Mark allocation/puntetoekenning: n(ccl4) at equilibriu = 0,9 ol / n(ccl4) by ewewig = 0,9 ol. Ratio/Verhouding: CS : Cl : SCl : CCl4 = 0,9 :,7 : 0,9 : 0,9 Equilibriu n(cs) & n(cl): initial change Ewewig n(cs) & n(cl): aanvanklik verandering Equilibriu: n(scl) = initial + change Ewewig: n(scl) = aanvanklik + verandering Divide ALL equilibriu nuber of oles by 5 d 3. Deel ALLE ewewigs getal ol deur deur 5 d 3. Correct Kc expression (forulae in square brackets). Korrekte Kc-uitdrukking (forules in vierkanthakies) Substitution of equilibriu concentrations into Kc expression. Vervanging van ewewigskonsentrasies in Kc-uitdrukking. Substitution of Kc value. / Vervanging van Kc-waarde. Final answer/finale antwoord: 4,9 Initial ol Aanvanklike ol Change in ol Verandering in ol Mole at equilibriu Mol by ewewig Equilibriu concentration Ewewigskonsentrasie (ol d -3 ) [S C ][CC 4 Kc = 3 [CS][C ] ] (0,45)(0,45) = 3 (0,5)(0,65) CS Cl SCl CCl4, ,9,7 0,9 0,9 0,3,3 0,9 = 4,9 38,6 54 0,5 0,65 0,45 0,45 = 0,9 Ratio/ Verhouding Divide by 5/Gedeel deur 5 No K c expression, correct substitution/ Geen K c-uitdrukking, korrekte substitusie: Wrong K c expression/verkeerde K c-uitdrukking: Max./Maks. 7 8 Max./Maks. 5 8 (8) Decreases / Verlaag () 6.3. Reains the sae / Bly dieselfde ()

9 Meo: PhySci P/Fis Wet V Gr 9 FSDoE/VSDvO Septeber Reactants were reoved./reaktanse is verwyder. OR/OF CS and/or Cl were reoved./ CS en/of Cl is verwyder. () 6.5 Incease / Verhoog () 6.6 With an increase in teperature, the rates of both the forward and reverse reactions increase. Met 'n verhoging in teperatuur verhoog die tepos van beide die vooren terugwaartse reaksies. The rate of the reverse endotheric reaction increases ore than that of the forward reaction. Die tepo van die terugwaartse endoteriese reaksie verhoog eer as dié van die voorwaarste reaksie. OR/OF The rate of the forward exotheric reaction increases less than that of reverse reaction. Die tepo van die voorwaarste eksoteriese reaksie verhoog inder as dié van die terugwaartse reaksie. The rate of the forward reaction then increases gradually due to the increase in concentration of reactants. / Die tepo van die voorwaartse reaksie verhoog dan stelselatig as gevolg van die verhoging in konsentrasie van reaktanse. The rate of the reverse reaction then decreases gradually due to the decrease in concentration of products. / Die tepo van die terugwaartse reaksie verlaag dan stelselatig as gevolg van die verlaging in konsentrasie van produkte. Equilibriu is reached after inutes / the rate of forward and reverse reactions are equal after inutes. Ewewig word na inute bereik / die tepo van voor- en terugwaartse reaksies is gelyk na inute. (5) [9]

10 Meo: PhySci P/Fis Wet V Gr 0 FSDoE/VSDvO Septeber 04 QUESTION Diprotic / Diproties () 7.. SO 4 () 7..3 Sulphate ion / Sulfaatioon () p = -log[3o + ] 0 = -log[3o + ] [3O + ] = 0 0 = ol d -3 [Cl] = ol d -3 n c = V n = n = 5 x 0 - ol (0,05 ol) (5) 7.. CO 3 + O CO + 3 O- Bal. Marking criteria/nasienriglyne Reactants Products Balancing Reaktanse Produkte Balansering Ignore/Ignoreer and phases / en fases Marking rule 3.0/Nasienreël 3.0 (3) 7..3 Burette / Buret ()

11 Meo: PhySci P/Fis Wet V Gr FSDoE/VSDvO Septeber POSITIVE MARKING FROM QUESTION 7... POSITIEWE NASIEN VAN VRAAG 7... Substitute cnao and VNaO / Vervang cnao en VNaO n(cl) = n(nao) Answer fro/antwoord van Q7.. n(cl) n(naco3) = ½n(Cl) Substitute 06 and n(naco3) into n. M Substitueer 06 en n(naco3) in n M Final answer / Finale antwoord:,0 g n(nao) = cbvb = (0,4)(30 x 0-3 ) = 0,0 ol n a nb n(cl in excess/in ooraat) = n(nao) = 0,0 ol n(cl reacted with/gereageer et NaCO3): n(cl) = n(initial) n(reacted with NaO) = 0,05 0,0 = 0,038 ol n(naco3 reacted): na nb na = (0,038) = 0,09 ol n b n M 0,09 = 06 =,0 g (6) [8]

12 Meo: PhySci P/Fis Wet V Gr FSDoE/VSDvO Septeber 04 QUESTION 8/VRAAG 8 8. X () 8. E o cell = E o cathode E o anode,53 = - 0,3 - E o anode E o anode =,66 V X = Al Notes/Aantekeninge Accept any other correct forula fro the data sheet. Aanvaar enige ander korrekte forule vanaf gegewensblad. Any other forula using unconventional abbreviations, e.g. E cell = E OA - E RA followed by correct substitutions: Max.4 5 Enige ander forule wat onkonvensionele afkortings gebruik bv. E sel = E OM - E RM gevolg deur korrekte vervangings : Maks. 4 5 (5) igher than / oër as Ag + is a stronger oxidising agent than Pb +. Ag + is 'n sterker oksideeriddel as Pb +. () 8.3. Al(s) Al 3+ ( ol d -3 ) Ag + ( ol d -3 ) Ag(s) OR/OF Al(s) Al 3+ (aq) Ag + (aq) Ag(s) OR/OF Al Al 3+ Ag + Ag (3) [] QUESTION 9/VRAAG 9 9. Electrolytic (cell) / Elektrolitiese (sel) () P () 9.. O + e - + O - ACCEPT/AANVAAR: X X 3+ Ag + Ag Marking criteria/nasienriglyne O + e - + O - ( ) O + e - + O - ( ) + O - O + e O - O + e - ( 0 ) ()

13 Meo: PhySci P/Fis Wet V Gr 3 FSDoE/VSDvO Septeber Q to/na P () 9..4 Water () 9.3 O + Cl - + O + Cl Bal. OR/OF O + NaCl + NaO + Cl Bal. Marking criteria/nasienriglyne Reactants Products Balancing Reaktanse Produkte Balansering Ignore/Ignoreer and phases / en fases Marking rule 3.0/Nasienreël 3.0 (3) [9] QUESTION 0/VRAAG 0 0. Percentage of fertiliser (N, P and K) present in the fertiliser. Die persentasie kunsis (N, P en K) teenwoordig in die kunsis. () A () 0.. C () 0..3 C () %N = 8 = 4% () OPTION /OPSIE % of 0 kg = 4,4 kg 4 x 4,4 =,96 kg 9 OPTION 3/OPSIE 3 % of 0 kg = 4,4 kg OPTION /OPSIE 4 x = 9,78% 9 9,78% of 0 kg =,96 kg 44,44% of 4,4 =,96 kg 0.4 N3 + SO4 (N4)SO4 Bal. Marking criteria/nasienriglyne Reactants Products Balancing Reaktanse Produkte Balansering Ignore/Ignoreer and phases / en fases Marking rule 3.0/Nasienreël 3.0 (3) (3) [] GRAND TOTAL/GROOTTOTAAL: 50