Name of Candidate:……………………………………………. Class:………………….
D
Quantitative analysis (salt analysis)
1. The pain experienced in a toothache can be reduced when traces of one of the salts in
PESTALOZZI
EDUCATION
CENTRE
the chemistry
syllabus gets into contact
with the affected area.
SENIOR SECONDARY SCHOOL
GRADE 11 END OF TERM III TESTS (2024)
CHEMISTRY
(5070/3)
TIME: 20 HOURS
Instructions to candidates.
Write your name and class in the space provided at the top of the paper.
There are two sections, A and B in this question paper.
Section A
Answer all questions from this section
Write your answers in the spaces provided on the question paper
Section B
Chose any three questions
Write the answers in the separate booklet provided.
For examiner`s use
Information for candidates
Section A
The number of marks is given in rackets [] at the end of each question
A10
or part of the question.
A11
The periodic table is printed on page 20
A12
A13
This question paper consists of 20 printed pages
PEC/2024/G11/P3/TERM3
0
Section A: [50 marks]
Answer all questions in the spaces provided.
A1.
(a). (i) Explain why most laboratories do not have smooth floors, but have rough
floors.
…………………………………………………..……………………………
…….……..………………………………………..………………………. [1]
(ii) Give one laboratory safety rule you would need to observe when carrying out
a titration experiment.
…………………………………………………..…………………………
…….……..……………………………………………..……………….
[2]
(b). Draw the arrangement of particles in a solid, liquid and gas in the spaces
below
[3]
Liquid
Solid
Gas
(c). Explain why
(i). for the space occupied, solids have higher density than liquids and gases.
………………………………………..…………………………….
[1]
(ii). Gases are compressible.
……………………………………………..……………………….
[1]
[Total: 7 marks]
1
A2.
The diagram below shows apparatus used in separating components of crude oil in
a school laboratory.
a.
Name the process by which crude oil is separated into other products on a
large scale.
………………………………………………………………………….. [1]
b.
What is the purpose of the cotton wool?
………………………………………………………………………….. [1]
c.
Why is the thermometer included in the diagram?
………………………………………………………………………….. [1]
d.
Why is the general term used to refer to substance X?
………………………………………………………………………….. [1]
[Total: 4 marks]
2
A3.
Crystals of Copper (ii) Sulphate (CuSO4.5H2O) are obtained from aqueous
solution of Sulphate (CuSO4).
State the four steps (processes) in their correct order, and for each step give the
reason for carrying out such step, in obtaining the crystals.
i.
Step 1……………………………………………………………………….
……………………………………………………………………………..
Reasons…………………………………………………………………….
………………………………………………………………………… [2]
ii.
Step 2……………………………………………………………………….
……………………………………………………………………………..
Reasons…………………………………………………………………….
………………………………………………………………………… [2]
iii.
Step 3……………………………………………………………………….
……………………………………………………………………………..
Reasons…………………………………………………………………….
………………………………………………………………………… [2]
iv.
Step 4……………………………………………………………………….
……………………………………………………………………………..
Reasons…………………………………………………………………….
………………………………………………………………………… [2]
[Total: 8 marks]
‘
3
A4.
(a).
A coefficient and subscript on the symbols of Nitrogen atom (N) mean
different notations in chemistry.
i.
What is the significant difference between the two notations 2N
and N2?
………………………………………...…………..………………
………………….……..……………………………………… [1]
ii.
Draw the dot and cross structures showing outer shells only
for the two notations.
(b).
[2]
N2
2N
Both Carbon tetrachloride (CCl4) and potassium Chloride (KCl) are
compounds of Chlorine.
i.
compare the electrical; conductivity of liquid Carbon tetrachloride
(CCl4) and potassium Chloride (KCl)
………………………………………...…………..………………
………………….……..…………………………………….... [1]
iii.
Which of the two compounds has a higher melting point.
Explain your answer.
………………………………………...…………..………………
………………….……..……………………………………….[2]
[Total: 6 marks]
4
A5.
A Grade 11 student at Pestalozzi Education center left a sample of iron filling in a
dump condition for the period of 24 hours. It was discovered that it developed
rust. He measured 3.5g of the sample and reacted it with aqueous Copper (ii)
Sulphate and 3.2g of Copper was formed.
Given that neither Copper Sulphate nor Iron fillings was in in excess during the
reaction.
a. Construct a balanced chemical equation for the reaction described above,
including the state symbols.
……………………………………………………………………………
[1]
b. Calculate the mass of Iron that reacted with aqueous Copper (ii) Sulphate.
[2]
c. Determine the percentage by mass on rust in the sample of Iron fillings.
[2]
d. Give one differences between electroplating and galvanizing as the
methods of preventing iron from rusting.
…………………………………………………………………………………
………………………………………………………………………………. [1]
[Total: 6 marks]
5
A6.
The diagram below shows how three compounds can be interconverted.
a.
Which of the three calcium compounds above:
i.
Occurs widely in nature?
……………………………………………………………..….. [1]
ii.
Is present in lime water?
……………………………………………………………..….. [1]
b.
Using the information in the diagram above,
i.
Suggest the substance that is added to calcium oxide to carry out
step 1
……………………………………………………………..….. [1]
ii.
Explain how step 3 can be carried out.
……………………………………………………………..….. [1]
[Total: 4 marks]
A7.
Lithium, Sodium, Potassium and Rubidium are members of group I of the
periodic Table.
a. What is the common name given to Group I elements?
………………………………………………………………………………. [1]
b. State two physical properties of Group I elements?
…………………………………………………………………………………
………………………………………………………………………………. [2]
c. Lithium reacts with water to form Lithium Hydroxide and Hydrogen gas.
Write a balanced chemical equation for this reaction.
………………………………………………………………………………. [2]
d. How would the sped of reaction of Lithium with water compare with that
of Rubidium with water?
…………………………………………………………………………………
………………………………………………………………………………. [1]
[Total: 4 marks]
6
A8.
Choose from the list of Oxides given to answer the questions that follow. An
oxide may be chosen once, more than once or not at all.
Name of the oxide
Its chemical
formula
Aluminium Oxide
Al2O3
Calcium Oxide
CaO
Carbon dioxide
CO2
Iron (iii) Oxide
Fe2O3
Water
H2O
Zinc Oxide
ZnO
Carbon Monoxide
CO
a. Which two Oxides are amphoteric?
…………….………………………….…………………….…………..........[1]
b. Which two Oxides are neutral?
…………….………………………….…………………….…………..........[1]
c. State the other types of oxides. Give an example of each oxide from the
table above
i.
…………………………….………………………….…………………
ii.
………………………….….………………………….……………. [2]
d. Suggest two Oxides which can be extracted from their metal ores using the
same method.
…………….………………………….…………………….…………...………
.………….…………………….………………………….……………...…. [2]
[Total: 6 marks]
7
A9.
The diagram below was used to measure the rate of reaction. The initial mass of
the beaker and the content was 50.0g
The graph below show also shows how the reaction between limestone and
hydrochloric acid proceeded with time.
8
a. What mass of carbon dioxide was lost when the reaction was completed?
[1]
b. Calculate the mass of calcium carbonate was used up in the first 2 minutes? [2]
c. On the same graph sketch how, the curve would appear if powdered
limestone was used.
[2]
[Total: 5 marks]
9
Section B (30 marks)
Answer three questions from this section
Write your answers in the Answer Booklet provided.
A10.
Zinc is extracted from its Sulphide Ore, Zinc blende, in a blast furnace shown below.
a. What reducing agent is used in the extraction process shown above?
[1]
b. What is the chemical name for Zinc Sulphide.
[1]
c. Write a balanced chemical equation for the reaction which occurs
when zinc blende is roasted in air.
[2]
d. Name a pollutant gas which is produced when zinc blende is roasted in air. [1]
e. Describe how the named pollutant in (d) is converted to a useful product
in industry.
f.
i.
ii.
[2]
Zinc is often alloyed with other metals. Name an element which
is alloyed with Zinc to form brass.
[1]
Give two use of Zinc.
[1]
[Total: 10 marks]
10
A11. A current of 0.5 amperes was passed for 2 400 seconds through colorimeters in
series. One colorimeter contains dilute sodium hydroxide and the other molten
potassium iodine. Graphite electrodes were used.
a. What quantity of electricity was used?
[2]
b. Write ionic equations for reactions occurring at the two anodes.
[2]
c. How many moles of electrons were passed through each electrolyte?
[2]
d. What mass of product is liberated at the cathode in the potassium iodide
voltmeter?
[2]
e. State any two applications of electrolysis.
[2]
[Total: 10 marks]
11
A12. The diagram below shows the energy-level diagram for a particular type of a
chemical reaction.
a. What does X shown in the diagram represent?
[1]
b. Is this reaction exothermic or endothermic? Give a reason for your answer.
[2]
c. Calculate the amount of heat change involved when 5.2g of glucose reacts
completely with oxygen.
[2]
d. Hydrogen combines with chlorine to form hydrogen chloride gas.
i.
Write balanced chemical equation for the reaction.
[1]
ii.
Calculate the enthalpy change for the reaction of hydrogen and
chlorine using the bond energies below.
bond
Bond energy (KJ/mol
H-H
436
Cl-Cl
242
H-Cl
431
[2]
iii. Is the reaction between Hydrogen and Chlorine exothermic or
endothermic? Justify your answer
[2]
[Total: 10 marks]
12
A13. The main ore of iron, Hematite, contains iron (III) oxide as its main constituent Iron
is extracted from this ore by chemical reduction in the blast furnace. The
temperature inside the furnace is about 2000°C.
a. Describe, with the aid of chemical equations how the carbon monoxide is
formed.
[2]
b. Write a balanced chemical equation for the reaction in which Iron Oxide
is reduced to Iron metal.
[2]
c. During the extraction of iron, molten slag is formed. Explain how slag is
produced during the extraction of Iron.
[2]
d. Most of the iron obtained in the blast furnace is converted into steel, which
is an alloy. Explain, with particular reference to iron, why metals are often
used as alloys rather than as pure metals.
[2]
e. A current of SOA is passed in the electrolyte for 1 hour. Calculate the mass of
Aluminium that will be produced. (1F = 1 mole of electrons = 96 500C).
[2]
[Total: 10 marks]
13
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