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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.
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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]
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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
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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]
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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.
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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
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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.
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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.
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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]
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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