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Form 1 Chemistry End of Term 3 Examination 2022

Class: Form 1

Subject: Chemistry

Level: High School

Exam Category: Form 1 End Term 3 Exams

Document Type: Pdf

Views: 1322 Downloads: 76

Exam Summary

Term 3 - 2022
CHEMISTRY(QUESTION PAPER)
FORM ONE (1)
Time: 2½ Hours
Name: …………………………………………………………. AdmNo: ……………….
School: ……………………………………………………….. Class: …………………..
Signature: …………………………………………………….. Date: …………………...
Instructions to candidate
a) Write your name, admission number, and stream in the spaces provided.
b) Answer ALL questions in the spaces provided
c) All working MUST be clearly shown where applicable
d) KNEC mathematical tables and silent non-programmable electronic calculators may be used
e) This paper consists of 11 printed pages
f) The candidate should check the question paper to ascertain that all the pages are printed as indicated and that no question is missing

1. Equal volumes of water in two separate boiling tubes were separately heated using two different Bunsen burner flames.

Sample 1 registered a higher temperature than sample 2.
a) Name and draw flame 2 (2 Marks)
Name _____________________________________________________________________
b) State the condition under which flame 1 is produced by a Bunsen burner (1 Mark)
___________________________________________________________________________
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2. The table below shows the colours obtained when some indicators were added to various solutions

a) Fill in the blank spaces in the table above? (3 Marks)
b) State the possible identity of Indicator W. (1 Mark)
___________________________________________________________________________
c) What is the advantage of using Indicator W? (1 Mark)
___________________________________________________________________________
3. State the laboratory rules that should be applied to prevent the following accidents:
a) Mistaking hydrochloric acid to be distilled water (1 Mark)
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b) A student got burnt after secretly lighting up a magnesium ribbon (1 Mark)
___________________________________________________________________________
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c) A student got severe stomach upset after eating some bread during a Chemistry laboratory session (1 Mark)
___________________________________________________________________________
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4. The setup below was arranged for the collection of dry hydrogen gas in the laboratory. Use it to answer the questions that follow.

a) Identify two mistakes in the set-up (2 Marks)
___________________________________________________________________________
___________________________________________________________________________
b) Suggest remedies for the mistakes identified in a) above (2 Marks)
___________________________________________________________________________
5. Dry hydrogen gas was passed over heated lead (II) oxide in a combustion tube as shown in the diagram below.

a) State two observations that were made in the combustion tube (2 Marks)
___________________________________________________________________________
___________________________________________________________________________
b) Write a word equation for the reaction taking place in the combustion tube (1 Mark)
___________________________________________________________________________
6. The products of a burning candle were passed through a U-tube containing anhydrous cobalt (II) chloride as shown in the diagram below

a) State the observation that was made in the U-tube (1 Mark)
___________________________________________________________________________
___________________________________________________________________________
b) Write a word equation for the reaction taking place in the U-tube (1 Mark)
___________________________________________________________________________
c) Name the gas that came out through tube R (1 Mark)
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7. Copper turnings were packed in a combustion tube connected to two syringes as shown in the diagram below. Syringe R contained 120cm3 of air while syringe S was empty.

The copper turnings were heated strongly as air was being passed from syringe R to syringe S slowly and repeatedly, until there was no further change in volume of air in syringe R. The final volume of air was 95.5cm3.
a) Why was air passed over the heated copper turnings slowly and repeatedly? (2 Marks)
___________________________________________________________________________
___________________________________________________________________________
b) State one observation made in the combustion tube during the experiment (1 Mark)
___________________________________________________________________________
c) Determine the percentage of oxygen used during the experiment (2 Marks)
___________________________________________________________________________
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8. The apparatus below was used to separate a mixture of liquid A and B

State two properties of the liquids that make it possible to separate them using this apparatus (2 Marks)
_____________________________________________________________________________
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9. A mixture contains iron filings, sulphur, and table salt. Describe a procedure that a student can use to separate the mixture and recover all the components of the mixture. (3 Marks)
______________________________________________________________________________
______________________________________________________________________________
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10.
a) Draw two separate diagrams to differentiate a flat-bottomed flask of 250ml and a volumetric flask of 250ml (2 Marks)
b) State the main use of a volumetric flask (1 Mark)
___________________________________________________________________________
___________________________________________________________________________
c) Flat bottomed flasks and volumetric flasks are made of glass. Explain (1 Mark)
___________________________________________________________________________
___________________________________________________________________________
11. The diagram below shows the cooling curve of a certain substance

Is this substance pure or impure? Explain (2 Marks)
______________________________________________________________________________
______________________________________________________________________________
12. Write word equations for the following reactions: (3 Marks)
a) Sodium and water
___________________________________________________________________________
b) Calcium oxide and nitric acid
___________________________________________________________________________
c) Magnesium carbonate and hydrochloric acid
___________________________________________________________________________
13. Salt is normally sprinkled on roads during winter in temperate countries.
a) State and explain why salt is put on roads during winter (2 Marks)
___________________________________________________________________________
___________________________________________________________________________
b) Why is this practice of great concern to motorists (1 Marks)
___________________________________________________________________________
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14. Explain how each of the following components is removed from a sample of air, before the fractional distillation of liquefied air:
a) Carbon (IV) oxide (1 Mark)
___________________________________________________________________________
___________________________________________________________________________
b) Water vapour (1 Mark)
___________________________________________________________________________
___________________________________________________________________________
c) Solid impurities (1 Mark)
___________________________________________________________________________
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d) Why is it important to remove carbon (IV) oxide from the air sample? (1 Mark)
___________________________________________________________________________
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15. Name the constituent element in each of the following compounds:
a) Copper (II) sulphate (1½ Marks)
___________________________________________________________________________
b) Sodium nitrate (1½ Mark)
___________________________________________________________________________
c) Potassium iodide (1 Mark)
___________________________________________________________________________
16.
a) Complete the table below (3 Marks)

a) What type of change is represented above? (1 Mark)
___________________________________________________________________________
b) Give four characteristics of the change (2 Marks)
___________________________________________________________________________
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18. Give any three apparatus that are used to measure accurate volumes of liquids and solutions in the laboratory (3 Marks)
______________________________________________________________________________
______________________________________________________________________________
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19. Define the following:
a) Boiling point (1 Mark)
___________________________________________________________________________
___________________________________________________________________________
b) Matter (1 Mark)
___________________________________________________________________________
___________________________________________________________________________
c) Indicator
___________________________________________________________________________
___________________________________________________________________________
20. Substance W is highly soluble in propanone, while substance M has low solubility in propanone. Which of the two substances will travel the shortest distance on an adsorbent material during paper chromatography? Explain (3 Marks)
______________________________________________________________________________
______________________________________________________________________________
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21. Name the following apparatus and state its use in the laboratory (2 Marks)

22. When separating solid copper (II) sulphate from a copper (II) sulphate solution, the solution was first heated then transferred to a water bath. Why was it important to heat the solution over a water bath? (2 Marks)
______________________________________________________________________________
______________________________________________________________________________
23. State two major differences between the properties of solids and those for gases (2 Marks)
______________________________________________________________________________
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24. After carrying out the process of distillation, describe how one can confirm that the distillate contains no dissolved solute (2 Marks)
______________________________________________________________________________
______________________________________________________________________________
25. Which method of separation can be used to obtain the following:
a) Petrol from crude oil (1 Mark)
___________________________________________________________________________
b) Oil from sunflower seeds (1 Mark)
___________________________________________________________________________
c) Distinguish between a homogenous mixture and heterogenous mixture (2 Marks)
___________________________________________________________________________
___________________________________________________________________________

Form 1 Chemistry End of Term 3 Examination 2022

Exam Summary

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