Chemistry Questions and Answers - Form 1 Mid Term 1 Exams 2023

QUESTIONS    

1. Define the term Chemistry. (1 mk)
2. State the major differences between the particles of solids and those of gases. (4 mks)
3. The diagram alongside shows a non-luminous Bunsen flame (burner).  Study it and answer the questions that follow. (3 mks)
           
   1. Name the labeled zones based on colour
      1. J –
      2. K –
      3. M –
   2. Which is the hottest part of the flame?  Give a reason for your answer. (2 mks)
   3. State what would happen if a wooden alighted, splint is placed at the free end of the glass tubing.  Explain. (2 mks)
   4. Why is this flame preferred to a luminous flame for heating purposes? (1 mk)
   5. Should the air hole be open or closed to produce this flame?  Explain.(2 mks)
   6.   A match-stick head placed in zone M will not ignite.  Explain. (2 mks)
4. Give a reason why a candle flame is not suitable for heating in the laboratory. (2 mks)
5. Besides a bunsen burner flame, name one other apparatus that can be used conveniently for heating in the laboratory. (1 mk)
6. Draw and name 4 common apparatus used in a chemistry laboratory. (4 mks)
7. State five laboratory rules observed in a Chemistry laboratory. (5 mks)
8. Identify the processes involved in the diagram below. (2 mks)
           
   1. A – (½ mk)
   2. B – (½ mk)
   3. C – (½ mk)
   4. D - (½ mk)
9. Name one career opportunity in Chemistry. (1 mk)
10.  
    1. What is drug abuse? (1 mk)
    2. What is a drug? (1 mk)
11. Explain why most laboratory apparatus are made of glass. (2 mks)
12. State four applications of paper chromatography. (4 mks)
13. State four characteristics of temperal physical changes  (4 mks)
14. Define each of the followiing terms
    1. Atom
    2. Element
    3. Compound
    4. Molecule
15. Name the elements present in:-
    1. Sodium bromide
    2. Zinc sulphide
    3. Magnesium nitride
    4. Potassium iodide

MARKING SCHEME

1. Define the term Chemistry. (1 mk)
   • It is the systematic study of chemical substances.
2. State the major differences between the particles of solids and those of gases. (4 mks)
   • Solids have fixed shape while gases have no fixed shape. (2 mks)
   • Solids have a fixed volume while gases have no fixed volume.
3. The diagram alongside shows a non-luminous Bunsen flame (burner).  Study it and answer the questions that follow. (3 mks)
   1. Name the labeled zones based on colour
      1. J – Blue zone
      2. K – Greenish-blue zone
      3. M – Colourless zone
   2. Which is the hottest part of the flame?  Give a reason for your answer. (2 mks)
      • Zone K
      • Gas burns completely and rapidly here.
   3. State what would happen if a wooden alighted, splint is placed at the free end of the glass tubing.  Explain. (2 mks)
      • Nothing – The gases in zone K completely burns out.
   4. Why is this flame preferred to a luminous flame for heating purposes? (1 mk)
      • It is hot and clean while aluminous flame is not hot enough and is sooty(dirty).
   5. Should the air hole be open or closed to produce this flame?  Explain.(2 mks)
      • Open
      • This provided entry for air which is necessary for combustion of the air.
   6. A match-stick head placed in zone M will not ignite.  Explain. (2 mks)
      • Zone M consists of unburnt gases and is therefore not hot.
4. Give a reason why a candle flame is not suitable for heating in the laboratory. (2 mks)
   • It is not hot enough
   • It is sooty
5. Besides a bunsen burner flame, name one other apparatus that can be used conveniently for heating in the laboratory. (1 mk)
   • Spirit lamp
6. Draw and name 4 common apparatus used in a chemistry laboratory. (4 mks)
7. State five laboratory rules observed in a Chemistry laboratory. (5 mks)
   • Proper dressing
   • Switching off all gas outlets/tap when not in use
   • Following all the instructions from technicians
   • Handling instruments with great care.
   • Opening all windows/doors when experiment is on.
8. Identify the processes involved in the diagram below. (2 mks)
   1. A – Melting (½ mk)
   2. B – Vaporisation/evaporation (½ mk)
   3. C – Deposition (½ mk)
   4. D - Sublimation (½ mk)
9. Name one career opportunity in Chemistry. (1 mk)
   • Medicine
   • Pharmacy
   • Nursing
10.  
    1. What is drug abuse? (1 mk)
       • Using a drug for a wrong purpose
    2. What is a drug? (1 mk)
       • Is any substance, natural or manufactured which when used alters the way the body functions.
11. Explain why most laboratory apparatus are made of glass. (2 mks)
    • Transparent, can see through
    • Do not react with most substances/chemicals
12. State four applications of paper chromatography. (4 mks)
    • In sports, used to identify banned substances
    • In the pharmaceutical industry, to test the purity of drugs
    • In food industry, to identify contaminants in food and drinks.
    • In cosmetic industry, to identify harmful substances.
13. State four characteristics of temperal physical changes. (4 mks)
    • Are easily reversible
    • No new substance formed
    • Mass of substance remains the same
    • Not accompanied by heat
14. Define each of the following terms: (4 mks)
    1. Atom – Smallest part of an element that takes part in a chemical reaction.
    2. Element – Pure substance that cannot be split into simple substance.
    3. Compound – Pure substance composed of 2 or more elements chemically combine.
    4. Molecule – Group of elements chemically combined together.
15. Name the elements present in:- (4 mks)
    1. Sodium bromide – Sodium bromide
    2. Zinc sulphide – Zinc sulphur
    3. Magnesium nitride – Magnesium Nitrogen
    4. Potassium iodide – Potassium, Iodine