Edgemead High School

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SOUTH AFRICAN COLLEGE HIGH SCHOOL

SOUTH AFRICAN COLLEGE HIGH SCHOOL

GRADE 10

PHYSICAL SCIENCE

EXAM 2009

EXAMINER: S.Pretorius

MARKS : 150TIME : 2 hours

INSTRUCTIONS

1. Answer ALL questions.

2. Non-programmable calculators may be used.

3. Appropriate mathematical instruments may be used.

4. A periodic table is provided for your use.



QUESTION 1

Possible answers are supplied with each question. Choose only the answer, whichin your opinion, is the correct or best one and cross the appropriate block on theanswersheet. Each question has only one correct answer.

1.1 Which of the following pairs of physical properties represent a pair of scalarsA velocity and timeB distance and timeC force and distanceD energy and displacement

1.2 A calcium ion Ca2+ has the same electron structure

(number of electrons) as …

A a calcium atom.

B a magnesium atom.C an argon atom.D a potassium atom. (3)

1.3 The wavelength of a sound wave travelling at 340m/s in air with afrequency of 300Hz is….

A 1.33 mB 0,88mC 3,4 mD 3,0 m

1.4 The following molecule is an example of polar covalent bonding..

A Cl2B NaClC HFD FBr

1.5 An atom of chlorine that has 18 electrons has …

A become a negative ion.B become a positive ion.C become a neutral atom.D an equal number of protons. (3)

[5x3=15]



QUESTION 2

Match the columns A and B by writing the corresponding letter next to the thequestion number.

[10]QUESTION 3

Give one word or phrase for the following.

3.1 A chemical bond which involves the sharing of electrons.3.2 A mixture in which particles of one liquid or solid are floating in aliquid or a gas.3.3 The process whereby two liquids with different boiling points can beseparated.3.4 The element represented by the electron configuration: 1s22s22p5

3.5 A compound that can conduct a current when dissolved in water.3.6 A reaction where energy is released.3.7 The elements in group 7 of the periodic table.

3.8 Electrons in the outer energy level of an atom.3.9 The measure of the tendency of an atom to attract a shared pair of

electrons ina covalent bond.

3.10 The element which is the main constituent of glass.[10]

Column A Column B

2.1 temperature2.2 pitch2.3 diatomic molecule2.4 Lewis structures2.5 ionic bond2.6 isotope2.7 loudness2.8 noble gas

2.9 Thompson2.10

a. crestb. oxygen in atmospherec. heliumd. carbon dioxidee. plum pudding modelf. amplitudeg.h. frequency

i. calcium chloride j. wavelenghtk. same number of protonsl. valence electronsm. average kinetic energy of

the particles



QUESTION 4

4.1 Write chemical formulas for the following

4.1.1 Potassium permanganate

4.1.2 Calcium chloride4.1.3 Sulphuric acid (3)

4.2 Write balanced equations for the following

4.2.1 Na2SO3 + HCl NaCl + SO2 + H2O (2)

4.2.2 K (s) + Cl2 (g) KCl (s) (2)

4.1.3 beryllium + oxygen beryllium oxide (4)

[11]

QUESTION 55.1 A beaker contains 71g of CaCO3 in solution. Calculate

5.1.1 The number of moles of CaCO3 in the beaker. (3)5.1.2 The number of oxygen atoms in the beaker. (3)5.1.3 The concentration of the CaCO3 solution. (3)

5.2 Consider the following balanced chemical equation.

Zn + 2H2SO4 ZnSO4 + SO2 + 2H2OCalculate the mass of zinc sulphate formed when 13,8g of zinc reacts tocompletion. (6)

[15]

QUESTION 6

The following reaction represents the industrial preparation of ammonia

3H2 (g) + N2 (g) 2NH3(g) + heat

From the list provided choose four that describes the reaction

Exothermic Decomposition Heterogenous Endothermic Redox Acid-base Homogenous Synthesis Addition Substitution

[4]



QUESTION 7

Redraw the representation of the periodic table on your answersheet and place the

corresponding letters ( A to J) onto the diagram using the clues provided.

• The atoms of A occur in period two and has one valence electron.

• B is a noble gas with 10 electrons.

• C is a gas which normally forms a ion with a charge of –2.

•

When D is without electrons it is known as an alpha particle.• E has the following valence electron structure 3s23p4.

• Element F is the gas that normally forms the ion F+.

• G is in group 4 and diamond and graphite are allotropes of G .

• H is an alkaline earth metal whose electrons are spread over three energylevels.

• All the isotopes of I has an atomic number of 11.

• The atoms of J are found in the same period as those of A, but has oneelectron in the p-orbitals.

• K is a metal found in period 3 group 3[11]

QUESTION 8

Study the diagram below which depicts the area of South Africabetween Johannesburg and Mpumalanga. Read the captions andanswer the questions below.



8.1 As the water vapour is mixing with the nitrous oxides, arethese chemicalsgoing through a chemical or physical change? Explain.(2)

8.2 What two processes (associated with the water cycle) must happenbetween the Vaal Dam and Johannesburg in order for acid rain to

form? (2)8.3 Why will there be more acid rain over the East Rand area

rather than overMpumalanga? Give two reasons

(2)8.4 The mortar used in buildings contains calcium carbonate.

Write a wordequation to show what happens to the calcium carbonate when

acid rainfalls onto the mortar. What effect do you think this will have on thebuildings?

(5)

8.5 Give two longer lasting effects that this increase in acid rainwill haveon the surrounding areas.(2)

[13]

QUESTION 9

9.1 Complete the following table about the atomic structures of some elements.You should refer to the Periodic Table on your data sheet



Atomicnumber

Number of protons

Number of electrons

Number of neutrons

Symbol

8 9

11 23Na

47 108Ag+

(9)

9.2 Potassium-40 (40K) is used to date very old rocks. Potassium also exists as 39Kand 41K. The atomic mass on the Periodic Table on the data sheet is 39.1

Explain how potassium can exist as these three isotopes and discuss anyconclusion that can be drawn from the given data. (5)

9.3 Write the electron arrangement (Aufbau diagram/ arrow in circle diagram) for the following.

9.3.1 a fluorine atom: (3)

9.3.2 an oxide ion (4) [21]

QUESTION 10

The Lewis diagram of a chlorine atom can be shown as:

Draw Lewis diagrams for the following:

10.1 nitrogen molecule (N2) (2)

10.2 methane molecule (CH4) (2) [4]

QUESTION 11

11.1 What’s the difference between a chemical and a physical change? (4)

11.2 Give four properties that are generally present in metals. (4)

11.3 If steel (a metal) is hard and granite (a non-metal) is hard, why don’t

we make automobile engines out of granite? (4)

11.4 What are metalloids used for, and how does this affect moderntechnology? (4)

[16]

QUESTION 12

The left-hand diagram is that of a table salt crystal. The right-handdiagram is that of water in a beaker. Study the diagrams and answerthe questions that follow.



12.1 What is the name of the solid structure that table salt forms?(1)

12.2 What kind of intramolecular bond exists in a salt molecule?(1)

12.3 What kind of bonding exists in the water molecule?(1)

12.4 What kind of intermolecular forces are identified in the right-handdiagram

by the arrow? (1)

12.5 Which of the bonds are stronger – intermolecular orintramolecular? (1)

12.6 After the salt is dissolved in the water, the solution is clear.Explain a

separation method that you could perform on this solution toseparate

the mixture.(2)

12.7 Write an equation for the reaction between table salt and water.(3)

[10]

QUESTION 13

Read the following article entitled “Saved by spiders” by RachelNowak, takenfrom New Scientist 8 June 2002. Write all answers in your own words.Anydirect quotes must be in inverted commas.



13.1 How are the webs that cribellate spiders weave different from thatof

other spiders? (2)13.2 As we know, air is a mixture. What kind of separation method are

thespiders using? (2)

13.3 How are the spiders being affected by this property of their webs?(2)

13.4 Explain why this scientist wants to try and use these webs as abiosensor.

(2)13.5 Give two places or scenarios where this idea used in 13.4 would be

useful.

(2)[10]



Chemical calculations Chemical constants

r M

mn =

V

nc =

Avogadro’s constant

6,02 x 1023

PERIODIC TABLE OF THE ELEMENTS

Atomic Number

Atomic Mass

1 2

3 4 5 6 7 8 9 10 11 12

13 14 15 16 17

18

1H

1.0

3Li

6.9

4Be

9.0

11Na

23.0

12Mg

24.3

2

He

4.0

5B

10.8

6C

12.0

7N

14.0

8O

16.0

9F

19.0

10Ne

20.2

13Al

27.0

14Si

28.1

15P

31.0

16S

32.0

17Cl

35.5

18Ar

40.0

19K

39.1

20Ca

40.1

21Sc

45.0

22Ti

47.9

23V

50.9

24Cr

52.0

25Mn

54.9

26Fe

55.9

27Co

58.9

28Ni

58.7

29Cu

63.6

30Zn

65.4

31Ga

69.7

32Ge

72.6

33As

74.9

34Se

78.9

35Br

79.9

36Kr

83.837

Rb

85.5

38

Sr

87.6

39

Y

88.9

40

Zr

91.2

41

Nb

92.9

42

Mo

95.9

43

Tc

(98)

44

Ru

101.1

45

Rh

102.9

46

Pd

106.4

47

Ag

107.90

48

Cd

112.4

49

In

114.8

50

Sn

118.7

51

Sb

121.8

52

Te

127.6

53

I

126.9

54

Xe

131.3

55

Cs

132.9

56

Ba

137.3

71

Lu

175.0

72

Hf

178.5

73

Ta

180.9

74

W

183.9

75

Re

186.2

76

Os

190.2

77

Ir

192.2

78

Pt

195.1

79

Au

197.00

80

Hg

200.6

81

Tl

204.4

82

Pb

207.2

83

Bi

209.0

84

Po

(209)

85

At

(210)

86

Rn

(222)

87

Fr

(223)

88

Ra

226.0

103

Lr

262.1

104

Rf

105

Db

106

Sg

107

Bh

108

Hs

109

Mt

57La

138.9

58Ce

140.1

59Pr

140.9

60Nd

144.2

61Pm

146.9

62Sm

150.4

63Eu

152.0

64Gd

157.3

65Tb

159.0

66Dy

162.5

67Ho

164.9

68Er

167.3

69Tm

168.9

70 Yb

173.0

89Ac

227.0

90Th

232.0

91Pa

231.0

92U

238.0

93Np

237.1

94Pu

239.1

95Am

241.1

96Cm

247.1

97Bk

249.1

98Cf

251.1

99Es

254.1

100Fm

257.1

101Md

258.1

102No

255

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