GRADE 11 NOVEMBER 2015 PHYSICAL SCIENCES P2 - … · NATIONAL SENIOR CERTIFICATE GRADE 11 NOVEMBER...

NATIONAL SENIOR CERTIFICATE

GRADE 11

NOVEMBER 2015

PHYSICAL SCIENCES P2

MARKS: 150 TIME: 3 hours

This question paper consists of 17 pages including 4 data sheets.

2 PHYSICAL SCIENCES P2 (EC/NOVEMBER 2015)

Copyright reserved Please turn over

INSTRUCTIONS AND INFORMATION 1. Write your full NAME and SURNAME in the appropriate spaces on the

ANSWER BOOK. 2. The question paper consists of EIGHT questions. Answer ALL the

questions. 3. Start EACH question on a new page in the ANSWER BOOK. 4. Number your answers correctly according to the numbering system used in

this question paper. 5. Leave ONE line open between sub-questions, for example QUESTION 2.1

and QUESTION 2.2. 6. A non-programmable calculator may be used. 7. Appropriate mathematical instruments may be used. 8. You are advised to use the attached DATA SHEETS and the PERIODIC

TABLE. 9. Shows ALL formulae and institutions in ALL your calculations. 10. Round off your final numerical answers to a minimum of TWO decimal

places. 11. Wherever motivations, discussions, etc. are required, be brief. 12. Write neatly and legibly.

(EC/NOVEMBER 2015) PHYSICAL SCIENCES P2 3


QUESTION 1: MULTIPLE-CHOICE QUESTIONS Four options are provided as possible answers to the following questions. Each question has only ONE correct answer. Write only the correct answer (A−D) next to the question number (1.1–1.10) in the ANSWER BOOK. 1.1 Iodine crystals (I2(s)) are soluble in ethanol (CH3CH2OH(l)) because

the … A hydrogen bonds between ethanol molecules are much stronger than

the dispersion forces between iodine molecules. B hydrogen bonds between ethanol molecules and the covalent bonds

between iodine molecules are of comparable strength. C iodine molecules and the ethanol molecules are non-polar and “like

dissolve like”. D London/dispersion forces between ethanol molecules and iodine

molecules are of comparable strength and “like dissolve like”. (2) 1.2 Which of the following solutions are considered to be electrolytes? (i) Sugar in water (C12H22O11(aq)) (ii) Table salt in water (NaCℓ(aq)) (iii) Hydrochloric acid (HCℓ(aq)) A (i) and (ii) B (i) and (iii) C (ii) and (iii) D (i), (ii) and (iii) (2) 1.3 0.5 dm3 of a gas at 20 °C and 130 kPa is cooled down while the volume is

kept constant. The pressure on the gas at a temperature of -5 °C is … A 142,13 kPa. B 123,34 kPa. C 118,91 kPa. D 32,5 kPa. (2) 1.4 The calculation in QUESTION 1.3 is an illustration of … A Avogadro’s Law. B Charles’s Law. C Guy-Lussac’s Law. D The ideal gas law. (2)



1.5 A pupil investigated Boyle’s Law and represented his results graphically:

p

The results show that: A p T1 T2

B p

T1 T2

C p T1 T2 D p T1 T2

(2) 1.6 Which ONE of the reactions below is a redox reaction? A 2H2(g) + O2(g) Æ 2H2O(g) B ZnSO4(aq) + H2S(g)) ÆZnS(s) + H2SO4(aq) C CO2(g) + Ca(OH)2(aq) Æ CaCO3(g) + H2O(l) D 2NH4Cℓ(s) + Ca(OH)2(s) Æ 2NH3(g) + CaCℓ2(s) + 2H2O(l) (2) 1.7 Consider the following acid-base reactions: NH3(g) + H2O(l) Æ NH4

+(aq) + OH-(aq) SO4

2-(aq) + HNO3(aq) Æ HSO4-(aq) + NO3

-(aq) The substances acting as proton acceptors in the above reactions are: A H2O and SO4

2- B NH3 and SO4

2- C NH3 and HNO3 D H2O and HNO3 (2) 1.8 Consider the following reversible reaction: H3O+ + OH- ↔ H2O + H2O The substance which is acting as an ampholyte is … A H3O+ ions. B OH- ions. C H2O molecules. D None of the above. (2)

T2

T1



1.9 Gold-bearing rock goes to a grinding mill where the ore is crushed into a

powder. The gold is removed from the powder by the following process: A Filtration B Adsorption C Smelting D Leaching (2) 1.10 Consider the following redox reaction: Zn + Au 3+ → Zn 2+ + Au Which of the following statements is INCORRECT? A Gold is recovered by a process of zinc precipitation. B Gold ions are oxidised in the recovery process. C Zinc displaces dissolved gold from a solution of its ions. D Zinc is added as a reducing agent during the recovery of gold. (2) [20]



QUESTION 2 (Start on a new page.) Consider the following molecules and answer the questions that follow.

A NH3

B CO2

C C2H2

D H20

E BH3 Which molecule: 2.1 2.1.1 Contains a triple bond? (1) 2.1.2 Is trigonal planar? (1) 2.1.3 Is angular in shape and contains a centre atom with two lone

pairs? (1) 2.2 Which TWO molecules can form a dative covalent bond with a hydrogen

ion? (2) 2.3 2.3.1 Draw a Lewis structure of the CO2 molecule. (2) 2.3.2 Briefly explain why the bonds shown in your answer to

QUESTION 2.3.1 are considered to be “polar covalent”. Refer to the difference in electronegativity of the atoms involved. (4)

[11]



QUESTION 3 (Start on a new page.) 3.1 For the substances mentioned in 3.1.1 to 3.1.3 write down the NAME of

the most important intermolecular forces: 3.1.1 Between the molecules in liquid methane (CH4) (1) 3.1.2 Between water and methanol (CH3OH) molecules in a mixture of

the liquids (1)

3.1.3 In an aqueous solution of lithium chloride (LiCl) (1) 3.2 Water has unique properties.

Complete the following table to show your understanding of some of these properties and the effect it has on our climate or living organisms.

Property of water 2 Reasons for

property Effect on our climate

or organisms

E.g.: High boiling point (1) Strong hydrogen bonds between molecules.

(2) Large amount of energy required to vaporise.

Most of the water on earth remain in the

liquid state.

High specific heat capacity 3.2.1 ... (2) 3.2.2 ... (1)

Density of ice less than that of water 3.2.3 ... (2) 3.2.4 ... (1)

High capillary action 3.2.5 ... (2) 3.2.6 ... (1)

(9) [12]



QUESTION 4 (Start on a new page.) 4.1 In an investigation into the relationship between the bond energy and

bond length a student looked up the bond energy between various pairs of atoms: He recorded his findings in the table shown below:

BOND LENGTH (pm) ENERGY kJ/mol C≡C 120 839 C=O 123 804 O=O 121 498 C–C 154 348 O–O 148 145 H–O 96 463 C–O 143 358 H–C 109 413 4.1.1 What is the INDEPENDENT VARIABLE in this investigation? (1) 4.1.2 What is the DEPENDENT VARIABLE in this investigation? (1) 4.1.3 Would this be considered a fair test? Write only YES or NO. (1) 4.1.4 Briefly explain your answer to QUESTION 4.1.3. (2) 4.2 Consider the combustion of 1 mol methane: CH4 + 2O2 → CO2+ 2H2O Use the values provided in the table given above to answer the following

questions: 4.2.1 What is the total amount of energy required to break all the

bonds in 1 mol CH4 and 1 mol O2? (4) 4.2.2 How much energy is released when bonds form to produce

2 mol of H2O and 1 mol of CO2? (4) 4.2.3 Hence calculate the energy transferred (ΔH) for the combustion

of 1 mol CH4. (2) 4.2.4 Draw a labelled energy profile for this reaction.

Include the labels: ENTHALPY CHANGE (ΔH) ACTIVATION ENERGY (Ea) (6)



4.3 Methanol (CH3OH) can also be burnt in O2 to produce energy or

decomposed to form hydrogen gas which is a useful fuel. Consider the following reaction where methanol is decomposed to form hydrogen: CH3OH(l) →2H2(g) + CO(g)

4.3.1 If 125 g of methanol is decomposed at STP, what is the theoretical

yield of hydrogen gas in dm3? (7) 4.3.2 If only 150 dm3 of hydrogen gas is obtained, what is the percentage

yield of the gas? (3) [31]



QUESTION 5 (Start on a new page.)

5.1 Gas A and Gas B have the same molecular mass. They are placed in

separate sealed containers. The containers are at the same temperature and have the same volume.

The density (number of molecules in a unit volume) of Gas A is greater

than the density of Gas B. 5.1.1 Which gas, A or B, exerts the greatest pressure on the walls of its

container? (1) 5.1.2 Explain your answer to QUESTION 5.1.1. (5) 5.2 Glass tubing is being chosen to produce a neon sign.

The glass must support 250 kPa without breaking. The design for the sign requires the use of 10,5 g Ne gas in a 6,77 dm3 volume. Operating temperature is expected to reach a maximum of 78 °C. Will this glass take the strain, or should tubing be sourced? (7)

5.3 Assume that oxygen is an ideal gas. 5.3.1 Complete the sketch graph below of pV versus T (in Kelvin) for the

gas at different values of temperature and pressure.

pV

T (2) 5.3.2 At very low temperatures it is found that the pV values for oxygen

no longer agree with those for an ideal gas. Assuming that no condensation has taken place, state how the pV values would deviate. Write only GREATER THAN or SMALLER THAN. (1)

5.3.3 Mention a single factor to which the deviation in QUESTION 5.3.2

can be ascribed to. (2) [18]

Container 1

Gas A

Container 2

Gas B



QUESTION 6 (Start on a new page.) 6.1 Hydrates are compounds containing water molecules loosely bound to

the other components. A 15 g sample of hydrated salt, Na2SO4 xH2O, was found to contain 7,05 g of water. Determine the value indicated by x in the empirical formula. (5)

6.2 6.2.1 Vinegar is a dilute form of acetic acid. A sample of acetic acid

has the following percentage composition: 39,9% carbon 6,7% hydrogen 53,4% oxygen Determine the molecular formula of acetic acid if the molar mass of acetic acid is 60 g∙mol-1. (6)

6.2.2 Give a reason why acetic acid is regarded as a monoprotic acid. (2) 6.3 Stomach acid is hydrochloric acid (HCℓ) and it has a pH of about 2.

Sometimes our stomachs produce too much acid and this causes heartburn. CaCO3 is available as an antacid tablet used to neutralise stomach acid.

6.3.1 Knowing that one of the products is CO2, write a balanced

equation for this neutralisation reaction. (3) 6.3.2 How much HCℓ (in mg) can be neutralised by a 500 mg tablet? (6) [22]



QUESTION 7 (Start on a new page.) A mixture containing a 100 g Aℓ and 200 g MnO was heated to initiate the following redox reaction:

2 Aℓ + 3MnO Æ Aℓ2O3 + 3Mn 7.1 7.1.1 Define oxidation. (2) 7.1.2 Give the value of the oxidation numbers of the underlined

elements. (2) 7.1.3 Identify the oxidising agent in the above-mentioned reaction.

Justify your answer by referring to oxidation numbers. (3) 7.2 The above-mentioned reaction will proceed until the limiting reactant is

completely consumed. Which reactant is the limiting reactant? Show your workings. (5)

7.3 Consider the following reaction:

H++ Cu +NO3

‒ →H2O + Cu2+ + NO 7.3.1 Use the ion-electron method to write half-reactions for oxidation

and reduction. (4) 7.3.2 Balance the reaction. (4) [20]



QUESTION 8 (Start on a new page.) 8.1 What is the lithosphere? (1) 8.2 In what form are most elements in the lithosphere found? (1) 8.3 In South Africa we have a lot of raw gold to be found in the earth. 8.3.1 Write down TWO ways in which gold is used in our everyday

lives. Refer to the properties of gold as a noble metal in your answer. (4)

8.3.2 The thermal decomposition of ammonium nitrate (an explosive

used in mining) produces a great many molecules in the gas phase so that there is a massive increase in volume. Consider the following equation: 2NH4NO3(s) →2N2(g)) + 4H2O(g) + O2(g)

How many litres (dm3) of gas will be produced if 320 g ammonium nitrate is heated at STP? (5)

8.3.3 State TWO ways in which the gold mining operation impact

negatively on ground. (2) 8.4 Cyanidation involves chemicals to extract gold:

4Au + 8CN- +O2 + H2O → 4[Au(CN)2]- + 4OH-

Refer to the equation given and briefly explain the process of cyanidation. (3)

[16] TOTAL: 150


TABLE 3: THE PERIODIC TABLE OF ELEMENTS/ TABEL 3: DIE PERIODIEKE TABEL VAN ELEMENTE

1 (I)

2 (II)

3

4 5

6

7

8

9

10

11

12

13 (III)

14 (IV)

15 (V)

16 (VI)

17 (VII)

18 (VIII)

2,1 1

H 1

2 He 4

1,0 3

Li 7

1,5 4

Be 9

2,0 5

B 11

2,5 6

C 12

3,0 7

N 14

3,5 8

O 16

4,0 9

F 19

10 Ne 20

0,9 11

Na 23

1,2 12

Mg 24

1,5 13

Aℓ 27

1,8 14

Si 28

2,1 15

P 31

2,5 16

S 32

3,0 17

Cℓ 35,5

18 Ar 40

0,8 19

K 39

1,0 20

Ca 40

1,3 21

Sc 45

1,5 22

Ti 48

1,6 23

V 51

1,6 24

Cr 52

1,5 25 Mn 55

1,8 26

Fe 56

1,8 27

Co 59

1,8 28

Ni 59

1,9 29

Cu 63,5

1,6 30

Zn 65

1,6 31

Ga 70

1,8 32

Ge 73

2,0 33

As 75

2,4 34

Se 79

2,8 35

Br 80

36 Kr 84

0,8 37

Rb 86

1,0 38

Sr 88

1,2 39

Y 89

1,4 40

Zr 91

41 Nb 92

1,8 42 Mo 96

1,9 43

Tc

2,2 44

Ru 101

2,2 45

Rh 103

2,2 46

Pd 106

1,9 47

Ag 108

1,7 48

Cd 112

1,7 49

In 115

1,8 50

Sn 119

1,9 51

Sb 122

2,1 52

Te 128

2,5 53

I 127

54 Xe 131

0,7

55 Cs 133 0,

9

56 Ba 137

57 La 139 1,

6

72 Hf

179

73 Ta 181

74 W

184

75 Re 186

76 Os 190

77 Ir

192

78 Pt

195

79 Au 197

80 Hg 201 1,

8

81 Tℓ

204 1,8

82 Pb 207 1,

9

83 Bi

209 2,0

84 Po

2,5

85 At

86 Rn

0,7 87

Fr

0,9 88

Ra 226

89 Ac

58 Ce 140

59 Pr

141

60 Nd 144

61 Pm

62 Sm 150

63 Eu 152

64 Gd 157

65 Tb 159

66 Dy 163

67 Ho 165

68 Er

167

69 Tm 169

70 Yb 173

71 Lu 175

90 Th 232

91 Pa

92 U

238

93 Np

94 Pu

95 Am

96 Cm

97 Bk

98 Cf

99 Es

100 Fm

101 Md

102 No

103 Lr

29 Cu 63,5

1,9 Simbool

Symbol

Elektronegatiwiteit Electronegativity

Benaderde relatiewe atoommassa Approximate relative atomic mass

Atoomgetal Atomic number

KEY/ SLEUTEL


DATA FOR PHYSICAL SCIENCES GRADE 11 PAPER 2 (CHEMISTRY) GEGEWENS VIR FISIESE WETENSKAPPE GRAAD 11 VRAESTEL 2 (CHEMIE) TABLE 1: PHYSICAL CONSTANTS/TABEL 1: FISIESE KONSTANTES NAME/NAAM SYMBOL/SIMBOOL VALUE/WAARDE

Avogadro's constant

Avogadro-konstante

N

A

6,02 x 10

23 mol

-1

Molar gas constant

Molêre gaskonstante

R

8,31 J∙K

-1∙mol

-1

Standard pressure

Standaarddruk

pᶱ

1,013 x 10

5 Pa

Molar gas volume at

STP Molêre gasvolume by

STD

V

m

22,4 dm

3∙mol

-1

Standard temperature

Standaardtemperatuur

Tᶱ

273 K

TABLE 2: FORMULAE/TABEL 2: FORMULES

=

=

or/of c =



TABLE 4A: STANDARD REDUCTION POTENTIALS TABEL 4A: STANDAARD REDUKSIEPOTENSIALE

Half-reactions/Halfreaksies θE (V)

F2(g) + 2e� ⇌ 2F� + 2,87 Co3+ + e� ⇌ Co2+ + 1,81

H2O2 + 2H+ +2e� ⇌ 2H2O +1,77

MnO�4 + 8H+ + 5e� ⇌ Mn2+ + 4H2O + 1,51

Cℓ2(g) + 2e� ⇌ 2Cℓ� + 1,36

Cr2O�2

7 + 14H+ + 6e� ⇌ 2Cr3+ + 7H2O + 1,33

O2(g) + 4H+ + 4e� ⇌ 2H2O + 1,23 MnO2

+ 4H+ + 2e� ⇌ Mn2+ + 2H2O + 1,23 Pt2+ + 2e� ⇌ Pt + 1,20

Br2(ℓ) + 2e� ⇌ 2Br� + 1,07

NO�3 + 4H+ + 3e� ⇌ NO(g) + 2H2O + 0,96

Hg2+ + 2e� ⇌ Hg(ℓ) + 0,85 Ag+ + e� ⇌ Ag + 0,80

NO�3 + 2H+ + e� ⇌ NO2(g) + H2O + 0,80

Fe3+ + e� ⇌ Fe2+ + 0,77 O2(g) + 2H+ + 2e� ⇌ H2O2 + 0,68

I2 + 2e� ⇌ 2I� + 0,54 Cu+ + e� ⇌ Cu + 0,52

SO2 + 4H+ + 4e� ⇌ S + 2H2O + 0,45 2H2O + O2 + 4e� ⇌ 4OH� + 0,40

Cu2+ + 2e� ⇌ Cu + 0,34

SO�2

4 + 4H+ + 2e� ⇌ SO2(g) + 2H2O + 0,17

Cu2+ + e� ⇌ Cu+ + 0,16 Sn4+ + 2e� ⇌ Sn2+ + 0,15

S + 2H+ + 2e� ⇌ H2S(g) + 0,14 2H+ + 2e� ⇌ H2(g) 0,00 Fe3+ + 3e� ⇌ Fe � 0,06 Pb2+ + 2e� ⇌ Pb � 0,13 Sn2+ + 2e� ⇌ Sn � 0,14 Ni2+ + 2e� ⇌ Ni � 0,27

Co2+ + 2e� ⇌ Co � 0,28 Cd2+ + 2e� ⇌ Cd � 0,40

Cr3+ + e� ⇌ Cr2+ � 0,41 Fe2+ + 2e� ⇌ Fe � 0,44 Cr3+ + 3e� ⇌ Cr � 0,74 Zn2+ + 2e� ⇌ Zn � 0,76

2H2O + 2e� ⇌ H2(g) + 2OH� � 0,83 Cr2+ + 2e� ⇌ Cr � 0,91

Mn2+ + 2e� ⇌ Mn � 1,18 Aℓ3+ + 3e� ⇌ Aℓ � 1,66

Mg2+ + 2e� ⇌ Mg � 2,36 Na+ + e� ⇌ Na � 2,71

Ca2+ + 2e� ⇌ Ca � 2,87 Sr2+ + 2e� ⇌ Sr � 2,89

Ba2+ + 2e� ⇌ Ba � 2,90 Cs+ + e- ⇌ Cs - 2,92 K+ + e� ⇌ K � 2,93 Li+ + e� ⇌ Li � 3,05

Incr

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TABLE 4B: STANDARD REDUCTION POTENTIALS TABEL 4B: STANDAARD REDUKSIEPOTENSIALE

Half-reactions/Halfreaksies θE (V) Li+ + e� ⇌ Li � 3,05 K+ + e� ⇌ K � 2,93

Cs+ + e� ⇌ Cs � 2,92 Ba2+ + 2e� ⇌ Ba � 2,90 Sr2+ + 2e� ⇌ Sr � 2,89

Ca2+ + 2e� ⇌ Ca � 2,87 Na+ + e� ⇌ Na � 2,71

Mg2+ + 2e� ⇌ Mg � 2,36 Aℓ3+ + 3e� ⇌ Aℓ � 1,66

Mn2+ + 2e� ⇌ Mn � 1,18 Cr2+ + 2e� ⇌ Cr � 0,91

2H2O + 2e� ⇌ H2(g) + 2OH� � 0,83 Zn2+ + 2e� ⇌ Zn � 0,76 Cr3+ + 3e� ⇌ Cr � 0,74 Fe2+ + 2e� ⇌ Fe � 0,44

Cr3+ + e� ⇌ Cr2+ � 0,41 Cd2+ + 2e� ⇌ Cd � 0,40 Co2+ + 2e� ⇌ Co � 0,28 Ni2+ + 2e� ⇌ Ni � 0,27

Sn2+ + 2e� ⇌ Sn � 0,14 Pb2+ + 2e� ⇌ Pb � 0,13 Fe3+ + 3e� ⇌ Fe � 0,06 2H+ + 2e� ⇌ H2(g) 0,00

S + 2H+ + 2e� ⇌ H2S(g) + 0,14 Sn4+ + 2e� ⇌ Sn2+ + 0,15 Cu2+ + e� ⇌ Cu+ + 0,16

SO�2

4 + 4H+ + 2e� ⇌ SO2(g) + 2H2O + 0,17

Cu2+ + 2e� ⇌ Cu + 0,34 2H2O + O2 + 4e� ⇌ 4OH� + 0,40 SO2 + 4H+ + 4e� ⇌ S + 2H2O + 0,45

Cu+ + e� ⇌ Cu + 0,52

I2 + 2e� ⇌ 2I� + 0,54 O2(g) + 2H+ + 2e� ⇌ H2O2 + 0,68

Fe3+ + e� ⇌ Fe2+ + 0,77

NO�3 + 2H+ + e� ⇌ NO2(g) + H2O + 0,80

Ag+ + e� ⇌ Ag + 0,80 Hg2+ + 2e� ⇌ Hg(ℓ) + 0,85

NO�3 + 4H+ + 3e� ⇌ NO(g) + 2H2O + 0,96

Br2(ℓ) + 2e� ⇌ 2Br� + 1,07 Pt2+ + 2 e� ⇌ Pt + 1,20

MnO2 + 4H+ + 2e� ⇌ Mn2+ + 2H2O + 1,23

O2(g) + 4H+ + 4e� ⇌ 2H2O + 1,23

Cr2O�2

7 + 14H+ + 6e� ⇌ 2Cr3+ + 7H2O + 1,33

Cℓ2(g) + 2e� ⇌ 2Cℓ� + 1,36

MnO�4 + 8H+ + 5e� ⇌ Mn2+ + 4H2O + 1,51

H2O2 + 2H+ +2 e� ⇌ 2H2O +1,77 Co3+ + e� ⇌ Co2+ + 1,81

F2(g) + 2e� ⇌ 2F� + 2,87

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NATIONAL SENIOR CERTIFICATE

GRADE/GRAAD 11

NOVEMBER 2015

PHYSICAL SCIENCES P2/ FISIESE WETENSKAPPE V2

MEMORANDUM

MARKS/PUNTE: 150

This memorandum consists of 9 pages./ Hierdie memorandum bestaan uit 9 bladsye.

2 PHYSICAL SCIENCES P2/FISIESE WETENSKAPPE V2 (EC/NOVEMBER 2015)


QUESTION 1 / VRAAG 1 1.1 D √√ 1.2 C √√ 1.3 C √√ 1.4 C √√ 1.5 A √√ 1.6 A √√ 1.7 B √√ 1.8 C √√ 1.9 D √ 1.10 B √√ (10 x 2) [20]

QUESTION 2 / VRAAG 2 2.1 2.1.1 C √ 2.1.2 E √ 2.1.3 D √ 2.2 A √ and/en D √ 2.3.1

√√ (2) 2.3.2 x Electronegativity difference 1 √√ / ( C-2.1 and O-3.5

) Verskil in elektronegatiwiteit

x Uneven √ sharing of electron pairs √ / O-atoms have stronger pull on shared electron pairs. Onewe deel van elektronpare / O-atome trek gedeelde elektronpare sterker aan. (4)

[11]

(EC/NOVEMBER 2015) PHYSICAL SCIENCES P2/FISIESE WETENSKAPPE V2 3


QUESTION 3 / VRAAG 3 3.1 3.1.1 Induced-dipole induced dipole √ / London / dispersion forces

Geїnduseerde-dipool geїnduseerde dipool / London dispersiekragte (1) 3.1.2 hydrogen bonds √ / waterstofbindings (1) 3.1.3 ion-dipole forces √ / ion-dipool kragte (1) 3.2 3.2.1 x Strong H-bonds between molecules √

x Large amount of energy absorbed for small change in temperature √

x Sterk H-binding tussen molekule x Groot hoeveelheid energie word vir ŉ klein toename in

temperatuur geabsorbeer. 3.2.2 x Moderate climate close to large bodies of water √ / organisms

can maintain steady body temperatures.

x Gematigde klimaat naby groot wateroppervlaktes / organismes kan ŉ konstante liggaamstemperatuur onderhou.

3.2.3 x Each molecule of water surrounded by 4 others √ / 3D-tetrahedral

shape x Structure with large open spaces. √

x Elke molekuul omring deur 4 ander watermolekules/ 3-D

tetrahedrale vorm x Struktuur met groot oop spasies.

3.2.4 x Water freezes from top down − capturing heat √ / aquatic

organisms stay alive below ice.

x Water vries van bo na onder – vang hitte vas / akwatiese organismes bly lewend onder die water.

3.2.5 x Strong adhesive forces √√

x Sterk adhesiekragte

3.2.6 x Water moves upward/and sideways √ to top branches and leaves

/ photosynthesis / transpiration.

x Water beweeg open sywaarts na boonste take en blare/ fotosintese / transpirasie. (9)

[12]



QUESTION 4 / VRAAG 4 4.1 4.1.1 bond length √ / bindingslengte (1) 4.1.2 bond energy √ / bindingsenergie (1) 4.1.3 NO √ / NEE (1) 4.1.4

or there is more than one independent variable√√ x The variables are not controlled √ / Die veranderlikes word nie

konstant gehou nie x Bonds should be between atoms of the same elements √ /

Bindings moet tussen atome van dieselfde elemente wees (2) 4.2 4.2.1 Energy required: 4x C-H √ = 4 x 413 = 1 652 √

2x O=O √ = 2 x498 = 996 √ (4) 4.2.2 Energy released: 2 x C=O √ = 2 x 804 = 1608 √

4x H-O √ = 4 x 463 = 1852 √ (4) 4.2.3 ΔH = (1 652 + 996) − (1 852 + 1 608) = 2648 – 3460 √ = -812 kJ √ (2)

4.2.4 Y-axis√ labelling X-axis√ labelling √ shape Ea √ Ea √ Act complex √ Shape √ ΔH√

Negative marking/Negatiewe merk

activated complex √ geaktiveerde kompleks

Ent

halp

y (k

J∙m

ol-1

) /

Enta

lpie

√

Ent

halp

y (k

J∙m

ol-1

) /

Enta

lpie

√

CH4+ 2O2

CO2 +2H2O

Progress of the reaction √ / Verloop van reaksie



4.3.1 n = √ = mol √

1 mol CH3OH : 2 mol H2 √ 3,906 mol : 7,8125 V =nVm √ = 7,8125 x 22,4 √ = 175 dm3 √ (7)

4.3.2

√ x 100% √ = 85,71% √ (3) [31] QUESTION 5 / VRAAG 5 5.1 5.1.1 A √ (1) 5.1.2 x consider/beskou: D =

= √

x If molar mass (M) and volume (V) is the same √ -– then D n √

As die molêre massa (M) en volume (V) dieselfde is – dan is D n

x Gas A has more particles than gas B √ / Gas A het meer deeltjies as gas B.

x More collisions with sides of container A √ Exert greater pressure in A. Meer botsings met die kante van houer A ŉ Groter druk word in A uitgeoefen. (5)

5.2 n =

= 0,525 mol √

pV = nRT

= ( )( )( ) = 226 192,799 Pa √ = 226,19 kPa Yes, it will take the strain. √ / Ja, dit sal die spanning kan weerstaan. (7)



5.3.1

pV √√ shape/vorm T (2)

5.3.2 GREATER THAN / GROTER AS √ (1) 5.3.3 Particles of a real gas have volume √√ / there are repulsive forces

between particles of a real gas Ware gasdeeltjies het volume / daar is afstotende kragte tussen die deeltjies van ŉ ware gas. (2)

[18] QUESTION 6 / VRAAG 6 6.1 M(Na2SO4) = 142 g∙mol-1 √

15 – 7,05 = 7,95g √ Na2SO4

n = = = 0,0559 mol √ Na2SO4

n = = = 0,392 mol √ H2O

Ratio 1 : 7 √ (5) 6.2 6.2.1 in 100 g:

= 3,325 mol C √ = 6,7 mol H√ = 3,3375 mol O √ Ratio: C1H2O1 √

M(C1H2O1) = 12 + 2(1)+16 = 30 g∙mol-1 √ and 60/30 = 2 Molecular formula / molekulêre formule: C2H4O2 √ (6)



6.2.2 acid donates √ 1 H+ ion √ / suur doneer (skenk) 1 H+ ion (2) 6.3 6.3.1 2HCℓ + CaCO3 √ CaCℓ2 + CO2 + H2O √√ balancing/balansering (3) 6.3.2 M(CaCO3) = 40 + 12 + 3(16) = 100 g∙mol-1 √

n = = = 0,005 mol √ CaCO3

1 mol CaCO3 : 2 mol HCℓ therefore/dus 0,005 : 0,01 mol HCℓ √ M(HCℓ) = 1 + 35,5 = 36,5 g∙mol-1 √ M = nM = 0,01(36,5) = 0,365 g = 365 mg √ stomach acid/maagsuur (6)

[22] QUESTION 7 / VRAAG 7 7.1 7.1.1 loss of electrons √√ / verlies aan elektrone (2) 7.1.2 MnO 2+ √

Aℓ2O3 3+ √ 7.1.3 MnO √ Mn2+ reduced √ to / gereduseer na Mn

decrease √ in oxidation numbers/ afname in oksidasiegetal OR oxidation number of Mn decreases from +2 to 0. √√ / OF oksidasiegetal van Mn neem af van +2 na 0. (3)

7.2 n = = = 3,7 mol Aℓ √

n = = = 2,82 mol MnO √

Aℓ : MnO ratio 2 : 3 1,88 mol Aℓ : 2,82 mol MnO √ Aℓ in excess and MnO the limiting reagent. √ / Aℓ in oormaat en MnO is die beperkende reagens (5)

7.3 7.3.1 Cu → Cu2+ + 2e- √

4H+ + NO3- + 3e- → NO + 2H2O √√√ (4)

7.3.2 Cu → Cu2+ + 2e- (x3) √

4H+ + NO3- + 3e- → NO + 2H2O (x2) √ 3Cu + 8H+ + 2NO3- √ → 3Cu2+ + 2NO + 4H2O √ (4)

[20]

Mark positively / Merk positief



QUESTION 8 / VRAAG 8 8.1 The earth’s crust and upper mantle / Die aardkors en boonste mantel √ (1) 8.2 As minerals / mineral ores √ (1) 8.3 8.3.1 ANY TWO / ENIGE TWEE / o.a.o.

x Money / gold bullion √ – valuable as it does not stain / corrode √ Geld / valuta − slaan nie aan of vlek nie.

x Decoration √ − malleable / can be rolled out in foils √ Versiering − pletbaar/ kan in dun goudfoelie gerol word

x Heat shield on spacecrafts √ – reflect sunlight √ / lustre Hitteskild op ruimtetuie- weerkaats sonlig / metaalglans

x Heating elements in aeroplane windows √ − reflect sunlight √ Verhittingselemente in vliegtuigvensters − weerkaats sonlig / metaalglans

x Jewellery √ − can be alloyed with cheaper metals to retain shape. √ Juwele − kan in allooi gemaak word met goedkoper metale wat vormbestand is.

x Electronic circuits √ − good conductor of electricity √ Elektroniese stroombane − goeie geleier van elektrisiteit

x Gold implants e.g. gold crowns in dentistry √ − will not rust /react with bodily fluids √ / bio-compatible.

x Goue ingeplante bv. goue krone in tandheelkunde − roesbestand en sal nie reageer met liggaamsvloeistowwe / bio-aanpasbaar. (4)

8.3.2 M(NH4NO3) = 2(14) + 4(1) + 3(16) = 80 g∙mol-1 √

n = = = 4 mol NH4NO3 √ 2 mol NH4NO3 : 7 mol gas 4 mol : 14 mol gas √ V= nVm= 14 (22,4) √ = 313,60 dm3 = 313,6 l of gas √ (5)



8.3.3 ANY TWO / ENIGE TWEE / o.a.o.

x Large areas of land deforested and water extracted – soil not

suitable for agricultural use / leads to erosion. Groot dele skoongemaak van plantegroei en water onttrek − grond nie geskik vir landbou / lei tot erosie.

x Water tables lowered – could lead to formation of sinkholes Watertafels verlaag − kan lei tot sinkgatvorming.

x Huge rocks removed and relocated/ mine dumps and tailing dams. Groot rotse word verwyder en verplaas / mynhope en afloopdamme.

x Silt containing heavy metals e.g. arsenic, cadmium and cobalt / radioactive particles. Slyk bevat swaarmetale bv. arseen, kadmium en kobalt / radioaktiewe deeltjies.

x Mudslides / modderstortings x Cyanide and sulphuric acid leaching into groundwater. /

Sianied en swawelsuur loog uit in grondwater in. x Acid mine drainage enters groundwater − unfit for consumption.

Suurmyndreinering gaan in grondwater in − nie geskik om te drink nie. (2)

8.4 x Crushed ore placed in tank with aqueous sodium cyanide √

Fyngemaakte erts word in ŉ tenk met waterige natriumsianied geplaas x In the presence of air (O2) a pulp is formed √ / oxidation takes place

In die teenwoordigheid van lug word ŉ pulp gevorm / oksidasie vind plaas

x Gold forms a soluble ion √ x Goud vorm ŉ oplosbare ioon. (3)

[16] TOTAL/TOTAAL: 150

GRADE 11 NOVEMBER 2015 PHYSICAL SCIENCES P2 - … · NATIONAL SENIOR CERTIFICATE GRADE 11 NOVEMBER...

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Transcript of GRADE 11 NOVEMBER 2015 PHYSICAL SCIENCES P2 - … · NATIONAL SENIOR CERTIFICATE GRADE 11 NOVEMBER...