EXAM COVER PAGE
Learner’s Name
PHYSICAL SCIENCE: FINAL EXAM PHYSICS – PAPER 2
DATE: 20 NOVEMBER 2015
TIME: 2 HOURS
EXAMINER: P. SNYMAN
MODERATORS: S.W.H. ENGELBRECHT, L. RETIEF, P. DE WET
GRADE: 10
TOTAL: 120
INSTRUCTIONS AND INFORMATION
1. Write your name on the ANSWER SHEET
2. Answer all the questions on the ANSWER SHEET
3. Read the questions carefully.
4. It is in your own interest to write legibly and to set your work out neatly.
5. Show your working in all calculations.
6. Where appropriate take your answers to 2 decimal places.
7. Units need not be included in the working of calculations, but appropriate units should be
shown in the answer.
8. You may use an appropriate mathematical calculator
9. Number the answers correctly according to the numbering which has been used in the
question paper.
10. You are advised to make use of the attached information sheets.
11. Hand in the Question Paper and Answer Sheet at the end of the session.
QUESTION 1
Four possible options are provided as answers to the following questions. Each question has only
ONE correct answer. Choose the best answer and write the correct letter next to the question
number on the ANSWER SHEET.
1.1
Of the reactions below, which one is a decomposition reaction?
A.
B.
C.
D.
1.2
Predict the product in this reaction: Al + N2 → ______________
A.
1.3
Al3N
C.
AlN2
D.
Al3N2
Calcium sulphide
Magnesium oxide
Sodium sulphide
Calcium bromide
mass number of X increases.
atomic number of X decreases.
charge of the nucleus increases.
number of filled energy levels decreases.
The number of atoms in ONE formula-unit of copper(II) sulphate (CuSO4) is:
A.
1.6
B.
When an atom X of an element in group 1 reacts to become X+, the
A.
B.
C.
D.
1.5
AlN
In which ONE of the following compounds do BOTH ions have the same electron
configuration as argon?
A.
B.
C.
D.
1.4
NH4Cl → NH3 + HCl
2MgO + O2 → 2MgO
2N2 + 3H2 → 2NH3
2CH4 + 4O2 → 2CO2 + 4H2O
4
B.
6
C.
16
D.
12
Which ONE of the following represents one mole of gas at STP?
A.
C.
22,4 dm3 Ar
32 dm3 H2
B.
D.
28 dm3 N2
44,8 dm3 He
1.7 Ethanoate is a radical or a compound ion with a charge of 1-. This radical has the following
formula: CH3 CO−
2 . Predict what the correct chemical formula of iron (III) ethanoate will be?
A. CH3CO2Fe3
B. (CH3)3CO2Fe
Physical Sciences Grade 10 Paper 2 November 2015
C.
CH3(CO2)3Fe
D.
(CH3CO2)3Fe
Page 2
1.8
In which of the following processes are covalent bonds broken?
A. I2(s) → I2(g)
C. NaCl(s) → NaCl(l)
1.9
As a Ca-atom undergoes oxidation to Ca2+, the number of neutrons in its nucleus:
A.
C.
1.10
B. CO2(s) → CO2(g)
D. C(diamond) → C(g)
decreases
remains the same
B.
D.
increases
first increases then decreases
The number of nucleons in a nucleus of an atom determines the ________________ of an
atom.
A.
Volume.
B.
Mass
C.
Size
D.
Energy.
2 x 10 = [20]
QUESTION 2
2.1
Solid carbon dioxide is sometimes known as dry ice. Under normal circumstances dry
ice sublimates as it warms up. Define the term "sublimation'.
(2)
2.2
When you take a block of butter out of the fridge, it is hard. However, after 15 minutes
at room temperature it is soft enough to spread. Use the kinetic theory to explain the
above observation.
(3)
2.3
The rate at which diffusion occurs depends on several factors. Two learners decided
to carry out an investigation on one of these factors. They set up the apparatus as
shown below with the two chemicals initially on the cotton wool at either ends of the
glass tube.
White cloud of NH4Cl
HCl(aq) on cotton wool
NH3(aq) on cotton wool
2.3.1 Write down the common name of NH3.
(1)
2.3.2 When NH3 and HCl meet they form a white ring in the glass tube. The white
ring is called ammonium chloride. Write down a balanced chemical equation for
the reaction that produces ammonium chloride.
(2)
2.3.3 Suggest, with a reason, which one of the substances on the cotton wool will
diffuse faster?
2.4
You hear someone says: “Diffusion occurs only in gases and does not take place in
the other states of matter.” Do you agree? Explain your answer.
Physical Sciences Grade 10 Paper 2 November 2015
(2)
(3)
[13]
Page 3
QUESTION 3
The heating curve for a pure substance at atmospheric pressure is shown in the graph below.
3.1
Use the information given in the graph and write down the following for this pure
substance:
3.1.1 Melting point.
(1)
3.1.2 Boiling point.
(1)
3.2
Is this pure substance water? Give a reason for the answer:
(2)
3.3
What is the physical state of the substance at:
3.4
3.3.1 Point X shown on the graph.
(2)
3.3.2 Room temperature.
(1)
What happens to the temperature while the substance melts? Explain this observation. (3)
[10]
Physical Sciences Grade 10 Paper 2 November 2015
Page 4
QUESTION 4
Sodium reacts with chlorine to form sodium chloride, a substance used in all households.
4.1
Write down:
4.1.1 Household name of sodium chloride.
(1)
4.1.2 Chemical formula of sodium chloride.
(1)
4.2
Write down a balanced chemical equation for the reaction of sodium and chlorine.
(3)
4.3
For the sodium atom write down its:
4.4
4.3.1 Electron configuration.
(2)
4.3.2 Number of protons.
(1)
Write down an equation of the reaction that will take place if you dissolve sodium
chloride in water. (Show the phases of each substance)
(2)
[9]
QUESTION 5
Information of six elements, represented as P, Q, R, S, T and Y, are given in the table below.
5.1
5.2
Which element (write only P, Q, R, S, T or Y):
5.1.1 Has 22 neutrons in each atom.
(1)
5.1.2 Is a noble gas.
(1)
5.1.3 Has TWO core electrons in each atom.
(1)
Two of the above elements are in the same group of the periodic table. Write down:
5.2.1 The letters representing these two elements.
(2)
5.2.2 Their group number on the periodic table.
(1)
Physical Sciences Grade 10 Paper 2 November 2015
Page 5
5.3
ONE of the elements represented above is potassium. Write down the:
5.3.1 Letter representing it.
(1)
5.3.2 The ion that it will form in a chemical bond.
(1)
5.4
Identify element S (write the name), AND write down its A
ZX notation.
(3)
5.5
Identify and write the NAMES of elements P, Q, R and T.
(4)
5.6
Write down the FORMULA of the compound formed by the combination of elements:
5.7
5.6.1 Q and P.
(1)
5.6.2 R and T.
(1)
Another element, X occurs in nature as two isotopes, X-23 and X-25. The drawing
shown below represents a sample of this element.
5.7.1 Define the term "isotope".
5.7.2 Use the above information and the diagram, to calculate the relative atomic
mass of element X.
(2)
(3)
[22]
QUESTION 6
Humphrey Davy was a professor of chemistry. In 1807 Davy did an electrolysis
experiment to produce potassium.
6.1 Davy first tried to electrolyse a solid potassium salt to produce potassium.
He found that the salt cannot conduct electricity and therefore could not use
this process to produce the potassium he wanted.
Name the type of bonding that occurs in a solid potassium salt and explain why it
does not conduct electricity.
(3)
6.2 When Davy electrolysed molten potassium chloride, potassium was produced at one
of the electrodes.
2KCl(ℓ) → 2K(s) + Cl2(g)
What type of chemical reaction is this?
Physical Sciences Grade 10 Paper 2 November 2015
(2)
[5]
Page 6
QUESTION 7
When a gummy bear (made up mostly of sucrose, C12H22O11(s)) is placed into a test tube of
heated potassium chlorate, a dramatic, explosive reaction occurs.
clamp
test tube
potassium chlorate
This reaction takes place in three steps:
KCℓO3(s)
Step 1:
KCℓO3(ℓ)
Step 2:
Step 3:
C12H22O11(s) + O2(g)
KCℓO3(ℓ)
KCℓ(s) + O2(g)
CO2(g) + H2O + energy
7.1 For each of the steps in this reaction above, say whether a physical or chemical change
is taking place:
7.1.1
step 1
7.1.2
step 3
7.2 Rewrite and balance the reaction represented in step 2.
(2)
(2)
7.3 State the type of reaction that is occurring in:
7.3.1
step 2
(1)
7.3.2
step 3
(1)
[6]
Physical Sciences Grade 10 Paper 2 November 2015
Page 7
QUESTION 8
8.1 The reaction between magnesium and diluted hydrochloric acid is represented by the
balanced equation below.
Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g)
During an experiment, 1,5 g of magnesium reacts with excess diluted hydrochloric acid
to produce hydrogen gas at STP.
Calculate the:
8.1.1 Mass (in gram) of hydrogen gas produced.
(6)
8.1.2 Volume (in dm3) of hydrogen gas produced at STP.
(3)
8.1.3 Number of chlorine atoms present in the MgCl2 produced.
(3)
8.2 The molar mass of hydrated sodium carbonate is found to be 268 g·mol-1.
The formula of the hydrated sodium carbonate is Na2CO3.xH2O. Calculate x.
(4)
8.3 The empirical formula of a certain compound is to be determined. On analysis of a
sample of the compound it was found to contain 24,27 % C, 4,07 % H and 71,65 % Cl.
8.3.1 Define the term empirical formula.
(2)
8.3.2 Determine the empirical formula of the compound. Show ALL calculations.
(4)
8.4 Diluted hydrochloric acid is poured over marble chips (calcium carbonate) as shown in
Figure 1 below.
8.4.1 Write a balanced chemical equation for the reaction between the hydrochloric acid
and marble chips.
(2)
8.4.2 What observation will be made from the reaction between the limewater and the
gas that is collected in the jar?
Physical Sciences Grade 10 Paper 2 November 2015
(1)
[25]
Page 8
QUESTION 9
For each of the following reactions, write down the:
a) Type of reaction that takes place (gas forming, precipitate, redox or acid-base) and
b) If the reaction takes place by means of electron transfer or ion exchange.
9.1 Mg(s) + FeSO4(aq) → MgSO4 (aq) + Fe(s)
(2)
9.2 Li2CO3 (aq) + 2HCl(aq) → 2LiCl (aq) + H2O (l) + CO2(g)
(2)
[4]
QUESTION 10
Solder (a substance used for joining metals) can be made by heating together the metals lead
and tin.
10.1 Is solder a homogenous mixture, heterogeneous mixture, pure substance or
compound?
10.2
Would you expect solder to have the same physical and chemical properties as its
constituent metals? Give a reason to your answer.
10.3 Three properties of solder are tested and compared to those of lead and tin – namely:
hardness, melting point and density. Are these physical or chemical properties?
(2)
(2)
(2)
[6]
GRAND TOTAL: [120]
Physical Sciences Grade 10 Paper 2 November 2015
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GRADE 10
FINAL EXAM: PHYSICAL SCIENCE (PAPER 2)
20 November 2015
___________________________________________________________________________
Answer Sheet
Name: ______________________
Question 1:
1.1 _______
1.2 _______
1.3 _______
1.4 _______
1.5 _______
1.6 _______
1.7 _______
1.8 _______
1.9 _______
1.10 _______
Physical Sciences Grade 10 Paper 2 November 2015
(10 x 2 = 20)
Page 10