NATIONAL CERTIFICATE (VOCATIONAL) PHYSICAL SCIENCE …

(10021004) -1-NC2330(E)(F)V

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PHYSICAL SCIENCE (Second Paper)

NQF LEVEL 4

(10021004)

15 March 2019 (X-Paper) 09:00–12:00

This question paper consists of 15 pages, 3 information sheets and 1 periodic table.

NATIONAL CERTIFICATE (VOCATIONAL)

(10021004) -2- NC2330(E)(M15)V


TIME: 3 HOURS

MARKS: 150

INSTRUCTIONS AND INFORMATION 1. 2. 3. 4. 5. 6.

Answer ALL the questions. Read ALL the questions carefully. Number the answers according to the numbering system used in this question paper. Use only blue or black ink. Approximate ALL final answers accurately to TWO decimal places. Write neatly and legibly.

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SECTION A QUESTION 1 Give ONE term for each of the following descriptions. Write only the term next to the question number (1.1–1.5) in the ANSWER BOOK.

1.1 Nuclear reaction that occurs in reactors generating electricity. 1.2 Mass per unit volume. 1.3 Physical quantity that indicates the average kinetic energy of the particles in a

substance.

1.4 Process by which nitrogen is extracted from the atmosphere. 1.5 Solution that resists changes in pH when an acid or alkali is added to the

solution. (5 × 1)

[5]

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QUESTION 2 Choose a description from COLUMN B that matches a term in COLUMN A. Write only the letter (A–I) next to the question number (2.1–2.5) in the ANSWER BOOK.

COLUMN A COLUMN B

2.1 2.2 2.3 2.4 2.5

Hydrocarbon Functional group Hydrogen bonding Addition Oxidation

A

B

C

D

E

F

G

H I

encourages the production of strong roots and stems occurs when the rate of the forward reaction equals the rate of the reverse reaction compound made up of carbon, hydrogen and oxygen only type of reaction characteristic of alkenes unstable, intermediate complex formed during the course of a reaction may be a chemical bond, atom or group of atoms that gives an organic compound its characteristic properties responsible for the relatively high boiling point of organic acids compound made up of carbon and hydrogen only occurs when an alkane burns in oxygen

(5 × 1) [5]

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QUESTION 3 Indicate whether the following statements are TRUE or FALSE. Choose the answer and write only 'True' or 'False' next to the question number (3.1–3.5) in the ANSWER BOOK.

3.1 Nuclear power reactors contribute to global warming by producing large

quantities of carbon dioxide.

3.2 Liquids and gases, such as air, are classified as fluids. 3.3 In an endothermic reaction the potential energy of the products is greater than

the potential energy of the reactants.

3.4 A weak base is a strong electrolyte. 3.5 Chemical equilibrium is reached in a closed system when the physical

properties of a chemical system become constant. (5 × 2)

[10]

QUESTION 4 Various options are given as possible answers to the following questions. Choose the answer and write only the letter (A–D) next to the question number (4.1–4.5) in the ANSWER BOOK.

4.1 The graph shows how the radioactivity of a particular isotope varies with time.

What is the half-life of this isotope? A

B C D

2,5 days 5,0 days 10,0 days 12,5 days

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4.2 The equation below represents the reaction that takes place when an organic

compound and concentrated sodium hydroxide are strongly heated. X represents the organic product formed.

CH3CHBrCH3 + NaOH → X + NaBr + H2O Which ONE of the following is the correct IUPAC name for compound X?

A

B C D

Propan-1-ol Propan-2-ol Prop-1-ene Prop-2-ene

4.3 A catalyst has the following properties:

i. It starts a reaction. ii. It is not used up in a chemical reaction. iii. It increases the rate of a chemical reaction. Which ONE of the following is true:

A

B C D

(iii) only (i) and (ii) only (i) and (iii) only (ii) and (iii) only

4.4 Which ONE of the following concerning the reaction in chemical equilibrium

below is true:

N2 (g) + 3H2 (g) 2 NH3 (g) ΔH < 0

A

B C D

Increasing the temperature decreases the concentration of NH3 in the reaction mixture. Decreasing the pressure increases the concentration of NH3 in the equilibrium mixture. Decreasing both pressure and temperature favours the forward reaction. The addition of a catalyst decreases the concentration of NH3 in the reaction mixture.

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4.5 When aqueous solutions of Ag+ and Fe2+ are mixed, Ag and Fe3+ form

according to the following chemical reaction:

Ag+(aq) + Fe2+(aq) Ag(s) + Fe3+(aq)

Which one of the following concentration versus time graphs best represents the way in which the Fe3+ concentration varies as the reaction proceeds to equilibrium?

A

C

B D

(5 × 3)

[15]

TOTAL SECTION A: 35

Time

Fe

3+ c

on

ce

ntr

atio

n

Time F

e3+ c

on

ce

ntr

atio

n

Time

Fe

3+ c

on

ce

ntr

atio

n

Time

Fe

3+ c

on

ce

ntr

atio

n

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QUESTION 5

5.1 Would you expect the hydrostatic pressure at a depth of 50 m in sea water to

be, greater than, equal to or less than at the same depth in fresh water? Explain the answer.

(3) 5.2 A hydraulic press consists of two plungers A and B in contact with a liquid.

The surface area of plunger A in contact with the liquid is 0,1 m2 and the surface area of plunger B in contact with the liquid is 0,35 m2, as shown in the sketch below. A force of 20 N is applied to plunger A in order to hold a block of unknown mass x stationary on plunger B.

5.2.1 Calculate the pressure exerted by plunger A on the surface of the

liquid.

(3) 5.2.2 Is the pressure exerted by the liquid on plunger B, greater than,

equal to or less than the pressure exerted by plunger A on the liquid? Explain the answer with reference to a relevant scientific principle.

(4)

5.2.3 Calculate the mass of block X. (3) [13]

B

A

x

0,1 m2

0,35 m2

20 N

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QUESTION 6 The letters A to F in the table below represent SIX organic compounds.

6.1 Write down the general formula of the homologous series to which compound

A belongs.

(1) 6.2 Is compound B saturated or unsaturated? Give a reason for the answer. (2) 6.3 Write a balanced chemical equation for the complete combustion of

compound C.

(3) 6.4 Write down the structural formula and name of the functional group present in

compound D.

(2) 6.5 Draw the full structural diagram and provide the IUPAC nomenclature of an

isomer of compound E.

(4) 6.6 Select a compound from the list that: 6.6.1 Is a reactant for the formation of polythene 6.6.2 Has a pH less than 7

(2 × 2)

(4)

A

D

B

E

C

butane

F

ethane

H 11

C 11

H 11

C C C H

H 11

H 11 H

11

C C C C

H H

H

H

H

H

H

H H 11

H 11

H 11

C C C O

H H 11

H 11

H

H

C C O H

H O

H

H

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6.7 Give the IUPAC nomenclature for: 6.7.1 Compound A 6.7.2

6.7.3

Compound B Compound D (3 × 2)

(6)

6.8 Explain why compound C has a higher boiling point than compound F. (2)

[24] QUESTION 7 A group of students use the reaction between solid zinc and an excess of hydrochloric acid solution to study two factors which affect the rate of chemical reactions. The reaction between zinc and hydrochloric acid solution is represented by the balanced equation below.

Zn(s) + 2HCℓ(aq) → ZnCℓ2(aq) + H2(g)

Two investigations (A and B) were conducted under the conditions indicated below:

7.1 INVESTIGATION A

7.1.1 Identify the independent variable in this investigation. (1) 7.1.2 Write down a hypothesis for this investigation. (2) 7.1.3 The learners now repeat Experiment 1 using HCℓ of the same

concentration but at a temperature of 30 0C. They find that the rate of the reaction INCREASES. Give an explanation as to why the reaction rate increases.

(3) 7.2 INVESTIGATION B:

Mass of Zn(s)

in g) State of Zn

Concentration of HCℓ (mol∙dm-3)

Temperature of HCℓ (°C)

Experiment 3 1,5 lumps 1,5 24


7.2.1 Write down an investigative question for this investigation. (2) 7.2.2 Is it fair to compare results obtained in Experiment 3 with that in

Experiment 4? Write down only YES or NO and give a reason for the answer.

(2)

Mass of Zn(s)

in g State of Zn

Concentration of HCℓ (mol∙dm-3)

Temperature of HCℓ (°C)

Experiment 1 2,5 powder 1,5 24


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7.2.3 The reactions in experiments 3 and 4 both run to completion. how

will the yield of h2(g) in experiment 3 compare to that in experiment 4? Write down only larger than, smaller than or equal to and give a reason for the answer.

(2) 7.3 The graph below shows changes in the potential energy for the reaction

between zinc and hydrochloric acid. Use the relevant energy values, A, B and C, to write down an expression for each of the following:

7.3.1 Activation energy for the forward reaction. (2) 7.3.2 ∆H for the reverse reaction. (2)

[16]

B

C

A

Course of reaction

Po

ten

tial

en

erg

y (

kJ)

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QUESTION 8

8.1 4 moles of nitrogen dioxide gas (NO2), 4 moles of sulphur dioxide gas (SO2) and 1 mole of sulphur trioxide gas (SO3) are allowed to react in a closed container of volume 2 dm3 at a temperature of 700 oC. The chemical equation for the equilibrium reaction is:

NO2(g) + SO2(g) SO3 (g) + NO(g)

After some time an analysis of the mixture showed that 1,8 moles of SO3 are present in the container.

If the equilibrium constant (Kc) is 9,0 at 700 oC; is the reaction in chemical equilibrium? Show all calculations to justify the answer.

(10)

8.2 Compare the rate of the forward reaction with the rate of the reverse reaction at this unknown time. Write down only equal to, faster or slower.

(2)

8.3 As the temperature increases, the Kc value increases. Is the forward reaction is endothermic or exothermic? With reference to Le Chatelier’s principle explain the answer.

(3) [15]

QUESTION 9 9.1 Ammonium chloride crystals, NH4Cℓ (s), dissolve in water to form ammonium

and chloride ions according to the balanced equation below:

NH4+(aq) + H2O(l) NH3(aq) + H3O

+(aq)

9.1.1 Write down the FORMULA of one conjugate acid/base pair. (2)

9.1.2 Write down the NAME of one ampholyte from the equation. (1)

9.2 9.2.1 A sea shell consists of 80 % calcium carbonate crystals. A sample

of mass x g of this sea shell was dissolved in 200 cm3 hydrochloric acid of concentration 1,5 mol.dm-3. The hydrochloric acid is in excess.

CaCO3 + 2HCℓ CaCℓ2 + H2O

Calculate the number of moles of hydrochloric acid in which the sample is dissolved.

(3)

9.2.2 In a titration, 25 cm3 of the excess hydrochloric acid solution is titrated with a 0,12 mol.dm-3 sodium hydroxide solution. At the end point it was found that 20 cm3 of the sodium hydroxide was used to neutralise the hydrochloric acid solution according to the following balanced equation: HCℓ (aq) + NaOH(aq) NaCℓ (aq) + H2O(l) Calculate the mass x (in grams) of the sea-shell sample used.

(8) [14]

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QUESTION 10 10.1 The flow diagram below shows the processes involved in the production of

fertilizer R. Write down the:

10.1.1 NAME of process P. (1) 10.1.2 NAME and FORMULA of product Q. (2) 10.1.3 FORMULA of fertiliser R. (1) 10.2 A 10 kg bag of NPK (40) fertiliser has an unknown NPK ratio. The mass of

nitrogen is 2,05 kg and the mass of phosphorus is 0,25kg.

10.2.1 What is the meaning of (40) on the label? (1) 10.2.2 Calculate the NPK ratio of the bag of fertiliser. (5)

[10]

PROCESS P CONTACT PROCESS

NH3 Q

FERTILISER R

(10021004) -14- NC2330(E)(M15)V


QUESTION 11 A voltaic cell was constructed by connecting a chromium half-cell to a metal Y half-cell as shown in the sketch below. In the external circuit electrons flow from the chromium electrode to metal Y. The initial voltmeter reading was 1,54 V.

11.1 Name TWO standard conditions for a voltaic cell. (2) 11.2 11.3

Explain the function of the salt bridge. Name a suitable chemical for use in the salt bridge.

(2) (1)

11.4 Is the net cell reaction exothermic or endothermic? (1) 11.5 When the cells delivers a current, will the concentration of Cr3+ increase,

decrease or remain constant? Write a balanced, half-reaction to explain the answer.

(3) 11.6 Identify metal Y. Clearly show all calculations. (4) [13]

Metal Y

Salt bridge

Cr3+ (aq)

Chromium electrode

V

Y+ (aq)

(10021004) -15- NC2330(E)(M15)V


QUESTION 12 A radioactive source is placed in a cylindrical hole drilled in a lead block. The radiation produced passes between TWO oppositely charged, parallel metal plates before striking a photographic plate.

12.1 Define radioactivity. (2) 12.2 Give TWO uses of nuclear radiation. (2 × 1) (2) 12.3 Identify the type of radiation indicated by each of the following: 12.3.1 Q 12.3.2 R

(2 × 2)

(4) 12.4 Why is the radioactive material placed in a lead block? (2) [10]

TOTAL SECTION B: GRAND TOTAL:

115 150

Photographic plate

Positively charged plates

Negatively charged plates Negatively charged plates

R

P

Q

Radioactive material

Lead block

(10021004) -1- NC2330(E)(M15)V


INFORMATION SHEET 1 TABLE 1: PHYSICAL CONSTANTS

NAME SYMBOL VALUE

Standard pressure p 1,013 × 105 Pa

Molar gas volume at STP Vm 22,4 dm3∙mol-1

Standard temperature T 273 K

TABLE 2: FORMULAE

M

mn

V

nc

OR

MV

mc

q = I t W = Vq

θ

anode

θ

cathode

θ

cell EEE

OR

θ

oxidation

θ

reduction

θ

cell EEE

OR

θ

agent reducing

θ

agent oxidising

θ

cell EEE

(10021004) -1- NC2330(E)(M15)V


INFORMATION SHEET 2

STANDARD REDUCTION POTENTIALS

Half-reactions θE (V) F2(g) + 2e ⇌ 2F + 2,87

Co3+

+ e ⇌ Co2+

+ 1,81

H2O2 + 2H+ +2e ⇌ 2H2O + 1,77

MnO

4 + 8H+ + 5e ⇌ Mn

2+ + 4H2O + 1,51

Cℓ2(g) + 2e ⇌ 2Cℓ

+ 1,36

Cr2O2

7 + 14H+ + 6e ⇌ 2Cr

3+ + 7H2O + 1,33

O2(g) + 4H+ + 4e ⇌ 2H2O + 1,23

MnO2 + 4H

+ + 2e ⇌ Mn

2+ + 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

SO2

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

Inc

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(10021004) NC2330(E)(M15)V

Copyright reserved

INFORMATION SHEET 3

STANDARD REDUCTION POTENTIALS

Half-reactions 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

SO2

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 ⇌ Mn

2+ + 2H2O + 1,23

O2(g) + 4H+ + 4e

⇌ 2H2O + 1,23

Cr2O2

7 + 14H+ + 6e ⇌ 2Cr

3+ + 7H2O + 1,33

Cℓ2(g) + 2e ⇌ 2Cℓ

+ 1,36

MnO

4 + 8H+ + 5e ⇌ Mn

2+ + 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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Copyright reserved

PERIODIC TABLE OF ELEMENT

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

Approximate relative atomic mass

Atomic number

29

Cu 63,5

1,9

Symbol

Electronegativity

KEY

(10021004) NC2330(E)(M15)V

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