TECHNICAL SCIENCES P2 TEGNIESE WETENSKAPPE V2 · 2019. 10. 7. · TECHNICAL SCIENCES P2 TEGNIESE...

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PREPARATORY EXAMINATION VOORBEREIDENDE EKSAMEN

GRADE 12/GRAAD 12

TECHNICAL SCIENCES P2 TEGNIESE WETENSKAPPE V2

SEPTEMBER 2019

MARKS/PUNTE: 150

MARKING GUIDELINES

NASIENRIGLYNE

This marking guideline consists of 12 pages./ Hierdie nasienriglyne bestaan uit 12 bladsye.

Technical Sciences P2/Tegniese Wetenskappe V2 2 FS/VS/September 2019 Grade/Graad 12 Prep. Exam./Voorb. Eksam.

Marking Guidelines/Nasienriglyn


QUESTION 1/VRAAG 1 1.1 B (2) 1.2 D (2) 1.3 D (2) 1.4 B (2) 1.5 D (2) 1.6 D (2) 1.7 A (2) 1.8 B (2) 1.9 C (2) 1.10 D (2)

[20] QUESTION 2/VRAAG 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 a CH2 group. 'n Reeks organiese verbindings wat deur dieselfde algemene formule

beskryf kan word en waarin elke lid van die volgende met 'n CH2-groep verskil. (2)

2.2 2.2.1 B (1) 2.2.2 E (1) 2.2.3 B OR/OF C (1) 2.2.4 D (1) 2.2.5 F (1) 2.3 2.3.1 Ketones/Ketone (1)




2.3.2 But-1-ene/1-butene

(2) 2.3.3 (2) 2.4 2.4.1 Compounds with the same molecular formula, but different (types of) chains. Verbindings met dieselfde molekulêre formule, maar verskillende (soorte) kettings. (2) 2.4.2 Methylpropane/2-methylpropane Metielpropaan/2-metielpropaan (2)

[16] QUESTION 3/VRAAG 3 3.1 An atom (or a group of atoms) that determine the chemistry of a molecule. (2 or 0) 'n Atoom (of 'n groep atome) wat die chemie van 'n molekuul bepaal. (2 of 0) OR/OF An atom (or a group of atoms) that determine(s) the physical and chemical properties of a group of organic compounds. (2 or 0) 'n Atoom (of 'n groep atome) wat die fisiese en chemiese eienskappe van 'n groep organiese verbindings bepaal. (2 or 0) (2) 3.2 Hydroxyl (group)/Hidroksiel(groep) (1) 3.3 3.3.1 Gases/Gasse (1) 3.2.2 Induced dipole (forces)/London (forces)/Dispersion (forces) Geïnduseerde dipool(kragte)/London(kragte)/Dispersie(kragte) (1)

Marking criteria/Nasienriglyne

Whole structure correct:

Hele struktuur korrek: 2 2

Only functional group correct:

Slegs funksionele groep korrek: 1 2

IF/INDIEN:

More than one functional group/Meer as een funksionele groep: 02

C C O C C

O H

H

H H

H

H

H

H

IF/INDIEN: butene/buteen Max/Maks.: 2

1




3.3.3 FROM A TO C/VAN A NA C:

Increase in boiling point./Toename in kookpunt.

Structure/Struktuur: Longer chain length / larger surface area (over which intermolecular forces act). Langer kettinglengte / groter oppervlak (waaroor intermolekulêre kragte werk).

Intermolecular forces/Intermolekulêre kragte: Stronger / more intermolecular forces / Van der Waals forces / London

forces / dispersion forces. Sterker / meer intermolekulêre kragte / Van der Waalskragte /

Londonkragte / dispersiekragte.

Energy/Energie: More energy needed to overcome or break intermolecular forces /

Van der Waals forces. Meer energie benodig om intermolekulêre kragte / Van der Waals- kragte te oorkom.

OR/OF FROM C TO A/VAN C NA A:

Decrease in boiling point./Afname in kookpunt.

Structure/Struktuur: Shorter chain length / smaller surface area (over which intermolecular forces act). Korter kettinglengte / kleiner oppervlak (waaroor intermolekulêre kragte werk).

Intermolecular forces/Intermolekulêre kragte: Weaker / less intermolecular forces / Van der Waals forces / London forces / dispersion forces. Swakker/minder intermolekulêre kragte / Van der Waalskragte / Londonkragte / dispersiekragte.

Energy/Energie: Less energy needed to overcome or break intermolecular forces / Van der Waals forces. Minder energie benodig om intermolekulêre kragte / Van der Waals- kragte te oorkom. (4)

3.4 3.4.1 ANY ONE/ENIGE EEN:

Only one independent variable. Slegs een onafhanklike veranderlike.

Compounds are of similar size. Verbindings is van soortgelyke grootte. (1)

3.4.2 Hydrogen bonding Waterstofbinding (1)




3.5 The pressure exerted by a vapour at equilibrium with its liquid in a closed system. /Die druk uitgeoefen deur 'n damp in ewewig met sy vloeistof in 'n geslote sisteem. (2) 3.6 A/Methane/Metaan Lowest boiling point/Laagste kookpunt (2)

[15] QUESTION 4/VRAAG 4 4.1 4.1.1 Hydrogenation/Hidrogenasie/Hidrogenering (1) 4.1.2 Hydration/Hidrasie/Hidratering (1) 4.2 4.2.1 H2/Hydrogen/Waterstof (1) 4.2.2 Pt/Ni/Pd/Platinum/Palladium/Nickel/Nikkel (1) 4.3 4.3.1 Addition/Hydrohalogenation/Hydrobromination Addisie/Hidrohalogenering/Hidrohalogenasie/Hidrobrominasie/ Hidrobrominering (1) 4.3.2 Bromoethane /Bromoetaan (2) 4.4 4.4.1 A chemical reaction in which monomer molecules join to form a polymer. 'n Chemiese reaksie waarin monomeer-molekule verbind om 'n polimeer te vorm. (2) 4.4.2 Ethene/Eteen (1) 4.4.3 Polyethene/Polythene Poli-eteen/Politeen (1) 4.4.4

(2)

4.5 (Excess) water/(Oormaat) water OR/OF Dilute strong base (Mild) heat/(Matige) hitte Verdunde sterk basis (2)

[15]

n

C C

H

H H

H


Structure with two C atoms and four H atoms as shown./Struktuur met twee C-atome en vier

H-atome soos getoon.

Structure in brackets with n as shown./

Struktuur in hakies met n soos aangedui.




QUESTION 5/VRAAG 5 5.1 5.1.1 A substance that gains electrons./'n Stof wat elektrone opneem. (2) 5.1.2 Ni/Nickel/Nikkel (1) 5.1.3 Ag+ + e- → Ag

(2) 5.2 5.2.1 (a) Salt bridge/Soutbrug (1) (b) Completes the circuit./Maintains electrical neutrality. Voltooi die stroombaan./Handhaaf elektriese neutraliteit. (1) 5.2.2 Temperature/Temperatuur: 25 °C Concentration of electrolytes/Konsentrasie van elektoliete: 1 mol·dm-3

(2) 5.2.3 Ni Ni is a stronger reducing agent. / Ni has a higher reducing ability. / Ni is the anode. / Ni loses electrons. / Ni is oxidised. Ni is die sterker reduseermiddel. / Ni het sterker reduseer vermoë. / Ni is die anode. / Ni verloor elektrone. / Ni word geoksideer. (2) 5.2.4 Ni (s) | Ni2+ (aq) || Ag+(aq) | Ag(s) OR/OF Ni (s) | Ni2+ (1 mol∙dm-3) || Ag+(1 mol∙dm-3) | Ag(s) Accept/Aanvaar: Ni | Ni2+ || Ag+ | Ag (3)

Marking guidelines/Nasienriglyne

Ag+ + e- ⇌ Ag 2

1 Ag ⇌ Ag+ + e- 2

0

Ag ← Ag+ + e- 2

2 Ag → Ag+ + e- 2

0

Ignore if charge omitted on electron./Ignoreer indien lading weggelaat op elektron.

If charge (+) omitted on Ag+/Indien lading (+) weggelaat op Ag+:

Max./Maks: 2

1 Example/Voorbeeld: Ag + e- → Ag




5.2.5 (4) 5.3 5.3.1 Chemical (energy) to electrical (energy) Chemiese (energie) na elektriese (energie) (1) 5.3.2 H2O/water (1) 5.3.3 ANY ONE/ENIGE EEN

Fossil fuels still needed/Fossielbrandstowwe steeds benodig (To produce hydrogen, fossil fuels are still needed./Vir die bereiding van waterstof word fossielbrandstowwe steeds benodig.)

Costly to produce/Duur om te produseer

Flammable/Vlambaar (Hydrogen is very prone to catching on fire, or even exploding./ Waterstof is baie geneig om vlam te vat of kan selfs ontplof.) (1)

[21] QUESTION 6/VRAAG 6 6.1 An electrochemical cell that converts electrical energy to chemical energy. 'n Elektrochemiese sel wat elektriese energie na chemiese energie omskakel. OR/OF A cell that uses electrical energy to decompose or break chemical compounds./'n Sel wat elektriese energie gebruik om chemiese verbindings te ontbind of breek. (2) 6.2 A to B (1) 6.3 A (A is the) positive electrode./(A is die) positiewe elekrode. (2)

Notes/Aantekeninge

Accept any other correct formula from the data sheet./Aanvaar enige ander korrekte formule vanaf gegewensblad.

Any other formula using unconventional abbreviations, e.g. E°cell = E°OA - E°RA followed by correct substitutions:/Enige ander formule wat onkonvensionele afkortings gebruik bv. E°sel = E°OM - E°RM gevolg deur korrekte

vervangings:

OPTION 2/OPSIE 2

Ag+ + e- Ag = 0,80 V

Ni Ni2+ + 2e- = +0,27 V

Ag+ + Ni Ag + Ni2+ = +1,07 V

OPTION 1/OPSIE 1 Eᶿcell = Eᶿcathode - Eᶿanode

= 0,80 – (-0,27) = 1,07 V




6.4 6.4.1 A substance of which the aqueous solution contains ions. 'n Stof waarvan die wateroplossing ione bevat.

OR/OF A substance that dissolves in water to form a solution that conducts

electricity. 'n Stof wat in water oplos om 'n oplossing te vorm wat elektrisiteit gelei. (2)

6.4.2 Cu2+/Cu(II) (1) 6.4.3 Cℓ‒ (1) 6.5 Cu/Copper/Koper (1) 6.6 (Gas) bubbles/Gas(borrels) Gas is released./Gas word vrygestel. (1) 6.7 2Cℓ‒ + 2e- → Cℓ2

Cℓ2 is a gas./Cℓ2 is 'n gas. (3) 6.8 ANY ONE/ENIGE EEN

Electroplating/Elektroplatering

Production of chemicals/Vervaardiging van chemikalieë (1) [15]

Marking guidelines/Nasienriglyne

Cℓ2 + 2e- ⇌ 2Cℓ− 2

1 2Cℓ− ⇌ Cℓ2 + 2e- 2

0

2Cℓ− ← Cℓ2 + 2e- 2

2 2Cℓ−- → Cℓ2 + 2e- 2

0

Ignore if charge omitted on electron./Ignoreer indien lading weggelaat op elektron.

If charge (-) omitted on Cℓ−/Indien lading (-) weggelaat op 2Cℓ−:

Max./Maks: 2

1 Example/Voorbeeld: Cℓ2 + 2e- → 2Cℓ




QUESTION 7/VRAAG 7 7.1 Refraction is the bending of light when it passes from one medium to another. Reflection is the change in direction of a wave upon striking the interface between two materials. Breking is die buiging van lig wanneer dit van een medium na 'n ander gaan. Weerkaatsing is die verandering in rigting van 'n golf wanneer dit die skeidingsvlak tussen twee materiale tref. (4) 7.2 (When a light ray is incident on a plane surface,) the incident ray, the reflected ray and the normal (to the surface) lie in the same plane and the angle of incidence is equal to the angle of reflection. (Wanneer 'n ligstraal op 'n plat oppervlak inval), is die invallende straal, weerkaatste straal en die normaal (op die oppervlak) in dieselfde vlak en die invalshoek is gelyk aan die weerkaatsingshoek. (2) 7.3 7.3.1 Angle of incidence/Invalshoek (1) 7.3.2 Angle of refraction/Brekingshoek (1) 7.3.3 Incident ray/Invallende straal (1) 7.3.4 Refracted ray/Gebreekte straal (1) 7.4 Medium B (1) 7.5 The light ray in the diagram bends towards the normal when entering medium B. Die ligstraal buig na die normaal toe waneer dit medium B binnegaan. (1) 7.6 The reflection of all light when light moves from an optical denser to an optical less dense medium. Weerkaatsing van alle lig waneer lig vanaf 'n opties digter na 'n opties minder digte medium beweeg. (2) 7.7 7.7.1 Y (1) 7.7.2 X OR/OF Z (1) 7.8 Greater than/Groter as (1) 7.9 Binoculars/telescopes/endoscope/periscope/fibre optic light Verkyker/teleskoop/endoskoop/periskoop/veseloptika lig ACCEPT/AANVAAR: fibre optics/veseloptika (1)

[18]




QUESTION 8/VRAAG 8 8.1 Breaking of white light into its component colours/seven colours/ colour band. Opbreek van witlig in sy samestellende kleure/sewe kleure/kleureband. (2) 8.2 Refraction/Breking (1) 8.3 Spectrum/Spektrum (1) 8.4 8.4.1 Red/Rooi (1) 8.4.2 Violet (1) 8.5 Violet light/ray 7 has the shortest wavelength.

When leaving from glass to air, the speed of violet light changes more than that of red light.

Violetlig/straal 7 het die kortste golflengte. Wanneer dit van glas na lug beweeg, verander die speod van violetlig meer as dié van rooilig. OR/OF Red light/ray 1 has the longest wavelength. When leaving from glass to air, the speed of red light changes less than that of violet light.

Rooilig/straal 1 het die langste golflengte. Wanneer dit van glas na lug beweeg, verander die spoed van rooilig minder as dié van violetlig. (2)

[8]




QUESTION 9/VRAAG 9

9.1 9.1.1 Convex/Konveks (1)

9.1.2 The image is enlarged – only a convex lens can form enlarged images. Beeld is vergroot – slegs konvekse lens kan vergrote beelde vorm. (1)

9.1.3 P (1) 9.2 9.2.1


Ray from object parallel to principle axis drawn OR ray from object through f of lens drawn./Straal vanaf voorwerp parallel aan hoofas getrek OF straal vanaf voorwerp deur f van lens getrek.

Ray drawn from object through optical centre of lens does not refract./Straal getrek vanaf voorwerp deur optiese middelpunt van lens getrek breek nie.

Ray from object parallel to principle axis through f after refraction OR ray from object through f parallel to principle axis after refraction./Straal vanaf voorwerp parallel aan hoofas deur f na breking OF straal vanaf voorwerp deur brandpunt van lens parallel aan hoofas na breking.

Two rays cross beyond 2f./Twee strale kruis verder as 2f. Image indicated by inverted arrow./Beeld deur omgekeerde pyl aangedui.

(5)

9.2.2 Real/Werklik (1) [9]

f

f 2f

2f

Lens

Object/Voorwerp

Image/Beeld




QUESTION 10/VRAAG 10

10.1 Changing magnetic and electric field perpendicular to each other and to

the direction of propagation of the wave. Veranderende magetiese en elektriese velde wat loodreg tot mekaar is en

tot die rigting van voortplanting van die golf. (2) 10.2 10.2.1 Infrared (radiation)/Infrarooi(straling) (1) 10.2.2 UV/ultraviolet (radiation)/UV-/ultraviolet(straling) (1) 10.2.3 Micro waves/Mikrogolwe OR/OF Radio waves/Radiogolwe (1) 10.3 10.3.1 A quantum/packet of energy. 'n Kwantum/pakkie energie. (2)

10.4.2 E = hf

3,44 ×10-23

= 6,63 × 10-34

f

f = 5,19 × 1010

Hz (3)

10.4.2 POSITIVE MARKING FROM QUESTION 10.4.2. POSITIEWE NASIEN VANAF VRAAG 10.4.2.

(3) [13]

GRAND TOTAL: 150

OPTION 1/OPSIE 1

c = fλ / v = fλ 3 x 108 = (5,19 x 1010)λ ∴ λ = 5,78 x 10-3 m

OPTION 2/OPSIE 2

E = hc

λ

3,44 × 10−23 = (3 × 108)(6,63 × 10−34)

λ

∴ λ = 5,78 x 10-3 m

TECHNICAL SCIENCES P2 TEGNIESE WETENSKAPPE V2 · 2019. 10. 7. · TECHNICAL SCIENCES P2 TEGNIESE...

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