20070No items in this section
20060No items in this section
20050No items in this section
2018 WASSCE (June) Integrated Science Paper Two – Essay
4. a) i) Define the term pressure.
ii) A regular concrete block weighing 5kg has dimensions 8 cm x 20 cm ? 50 cm. Calculate the greatest possible pressure the block will exert on the ground.
[g = 10 m s -2]
b) i) Give three reasons why poultry farms should be distanced from residential areas
ii) Mention two methods of preserving poultry egg.
c) State two causes each of the following problems associated with reproduction in
i) ectopic pregnancy;
ii) infertility in men.
d) Indicate whether each of the following substances Is an element, a compound or a mixture:
i) iron filings;
iv) milk of magnesia;
v) iodine crystals.
a) i) Definition of pressure
It is the force exerted (normally) on a unit area.
ii) Calculation of greatest pressure
P = F/A
where P is the pressure, F is the force and A is the area. Therefore the greatest pressure is exerted on the smallest area.
Area is given by: A=1xb
= A=(20×10-2)x (8×10-2) =0.016m2
Therefore P = F/A = 50/0.016 = 3125 pascals
b) i) Reasons why poultry farm should be distanced from residential address
To prevent obnoxious gases (ammonia or co2) from entering peoples’ houses.
To avoid disturbance from noise of poultry.
To enable fowls to receive enough natural air.
For the avoidance of dust spread into the pens.
For the avoidance of transfer of diseases into the pen.
ii) Methods of preserving poultry eggs
Cold storage or refrigeration or freezing;
Frozen liquid eggs;
Use of sodium silicate solution;
Keeping under dry sand;
Coating egg with mineral oil or vaseline;
Covering eggs with lime solutions;
Avoid changing the temperature of the egg;
Avoid washing the eggs;
c) i) Causes of ectopic pregnancy
pelvic inflammatory disease or bacterial infection in the neck of the womb or blockage of the tube;
surgery involving the fallopian tube or pelvic area or female sterilization;
endometriosis or abnormal growth of tissue of uterus;
genetic abnormalities or birth defects or history of ectopic pregnancy;
contraception or intrauterine device or system;
fertility treatments or taking medication to stimulate ovulation or in-vitro fertilization;
scar in the tube
ii) Causes of infertility in men
Blockage of vas deferens or epididymis or defects in the tubules;
Low sperm count or no sperms or high sperm mortality or abnormally-shaped sperm or inferior quality sperms or exposureto chemicals (or metals) or x-rays or over-use of electrical gadgets;
Sperm allergy or some men have an immune reaction to semen which causes them to produce anti-sperm antibodies that damage their sperms;
Surgeries on the testicles or vasectomy or hernia or prostate;
Genetic defects or chromosomal defects;
Health problems (tumours or diabetes or previous infections such as mumps or gonorrhea or stis or spinal injuries or medication);
Erectile dysfunction or premature ejaculation or reduced libido;
Alcohol or drugs;
d) Classification of substances
Water – Compound
Iron Filings – Element
Glass – Compound
Milk Of Magnesia – Mixture
Iodine Crystals – Element
5. a) A 0.04g of copper metal reacts completely with 25 cm3 of 0.5 mol dm-3 H2SO4
i) Write a balanced chemical equation for the reaction.
ii) Calculate the molar mass of the copper metal.
b) i) give two functions of the human ear.
iii) Arrange the following media in order of increasing speed of sound in each of them: solids, liquids and gases.
c) Give two advantages of clayey soil ever sandy soil.
ii) State three symptoms of nitrogen deficiency in maize.
d) State four ways in which biotic factors are useful in an ecosystem.
i) The balanced chemical equation for the reaction is:
Cu + 2H2SO4 –> CuSO4 + 2H2O + SO2
ii) Calculation of molar mass of copper metal
n(H2SO4) = (25?0.5)/1000
(n(Cu))/(n(H2SO4)) = 1/2 –> n(Cu) = (n(H2SO4))/2
? n(Cu) = (25?0.5)/(1000 ? 2)
But n(Cu) = mass/(molar mass)
(25 ?0.5)/(1000 ?2) = 0,04/(molar mass)
? Molar mass = (0.04 ?1000 ?2)/(25 ?0.5) = 6.4 g/mol
i) Functions of the ear
The ear is used for hearing
The ear is used for balancing
ii) Arrangement of the media in order of increasing speed of sound is as follows: Glasses ? liquids ? solids
i) Advantages of clayey soil over sandy soil
Clayey soil contains high amount of nutrients.
Clayey soil retains high amount of water or moisture.
Clay can be moulded into various shapes when wet.
Clay is not easily eroded due to its compact nature.
Clay does not heat up easily.
ii) Symptoms of nitrogen deficiency in maize
Poor or stunted growth.
Yellowish colourization of leaves or chlorosis or pale green leaves
Ways in which biotic factors are useful in an ecosystem
Birds or insects are agents for pollination.
Animals are agents for fruit or seed dispersal.
Trees provide shelter or shade to animals or other plants.
Bacteria or fungi help to decompose organic matter.
There is control of pests by specific predators.
They involve organisms in a mutualistic relationship.
Trees provide habitat for living organisms.
6. Question 6
a) i) State three ways through which AIDS is transmitted.
ii) List three effects of drug abuse on the user.
b) Name four endocrine glands found in humans.
c) i) What is shadow?
ii) Draw a ray diagram to illustrate a ray of light travelling from glass to air.
d) i) Explain ther term artificial insemination as used in animal production.
ii) State three advantages of artificial insemination in animal production.
a) i) AIDS is transmitted through:
• sexual intercourse
• blood transfusion
• infected mother to foetus during birth
• injection with infected needled
• blood to blood contact with an infected person
ii) Effects of drug abuse on the user
1. it affects user’s health or weakens the immune system of the user OR it causes cardiovascular problems or stroke or loss of appetite.
2. It leads to wastage of money
3. It leads to prostitution
4. Drug abuse leads to accidents
5. It causes premature death
6. It enhances criminal tendencies
7. Drug abuse affects the brain
8. It results in birth defects
9. It causes behavioural patterns or aggressiveness or hallucination or addiction or it impairs judgements or results in loss of self-control.
b) Names of endocrine glands found in humans are:
1. Pituitary gland
2. Thyroid gland
3. Adrenal gland
c) i) A shadow is the image formed of an object which lies in the path of light
ii) Ray diagram of light travelling from glass to air is as follows:
[[[ Diagram needed ]]]
• IR = incident ray;
• RR = refracted ray;
• r = angle of incidence;
• i = angle of refraction;
d) i) Explanation of the term artificial insemination
It is a process in which sperm or semen is introduced into the reproductive system of a female animal using special device without or without copulation so as to impregnate the animal.
ii) Advantages of artificial insemination
1. It takes away the problem of transporting male animals from one region to another for breeding purposes.
2. It ensures effective use of semen or sperm, OR it avoids wastage of semen or sperm.
3. It helps to prevent vencreal diseases OR it helps in disease control.
4. It helps overcome physical incompability between males and females.
5. It promotes controlled breeding.
6. It ensures fertilization of egg.
7. One male can be used to fertilize thousands of females.
8. It decreases chances of injuries.