2021-06-01 11:55:59
2021 Wassce Science trails
1. a) i) Define each of the following terms:
?) compound;
?) mixture
ii) State two differences between an element and a compound.
.
b) Explain each of the following terms:
i) greenhouse effect;
ii) climate change.
c) i) What is electrical rectification?
ii) Using simple wave diagrams, explain half-wave rectification.
d) State one way in which each of following environmental factors important to the life cycle of crops:
i) rainfall;
ii) temperature;
iii) sunshine,
iv) wind.
2. a) i) Give three reasons why goats are not normally kept under the intensive system of management.
ii) Name two diseases that affect rabbits.
b) i) Draw the structure of 11Na+
ii) State two differences between organic compounds and inorganic compounds.
c) i) What are decomposers?
ii) Name three common decomposers in an ecosystem.
d) i) Name three structures in the middle ear that help in the transmission of sound waves;
ii) Mention two ways in which earmuffs are important.
3. a) An electrical appliance rated 1.5 kW, 240 V is left running for 2 hours. Calculate the
i) current drawn;
ii) electrical energy consumed.
b) i) In what two ways does mulching help to conserve the soil?
ii) Give two examples of mulching
c) i) What is pollution?
ii) List three major atmospheric pollutants
d) i) State two benefits of each of the following minerals to the human body.
?) potassium;
?) calcium.
ii) Name one source of each of the minerals listed in d) (i).
4. a) i) State the method of preparing a salt from each of the following pairs of substances:
?) dilute tetraoxosulphate(VI) acid and dilute sodium hydroxide;
?) lead(ll) trioxonitrate(V) and sodium chloride
ii) Write a balanced equation for the reaction between lead(ll) trioxonitrate (V) and sodium chloride.
b) i) What are tidal waves?
ii) State four ways in which water could be contaminated.
c) i) State two ways in which legumes are important in crop production.
ii) State three advantages of crop rotation.
d) i) State three qualities of a good thermometric liquid;
ii) Give two precautions that must be taken when using a liquid-in-gas thermometer.
5. a) State:
i) two functions of the placenta in mammals;
ii) two structural features of the placenta which adapt the placenta to its functions.
b) Explain why each Of the following pairs of molecules are isotopes.
i) [formular required]
ii) [formular required]
c) List five farming practices that check soil erosion.
d) i) Arrange the following stages of water treatment for public consumption in the correct order:
chlorination, sedimentation, screening, sand filtration and aeration.
ii) State the significance of each of the following stages in water treatment:
?) screening;
?) filtration;
Y) chlorination
6. Question 6
a) State five post planting practices on cereal farm to ensure a high yield.
b) i) Define mechanical advantage of a simple machine.
ii) Give two examples of second class levers.
c) i) Name four apparatus needed in the preparation of a standard solution.
ii) Calculate the volume of water needed to dilute 20 cm3 of 5.0 M HCI to 1.0 M HCI solution. [H- 1.0, Cl = 35.5]
d) i) State three differences between hypogeal germination and epigeal germination.
ii) Give one example of seeds that undergo:
?) hypogeal germination;
?) epigeal germination.
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