KUULCHAT
S.H.S SCIENCE MOCK
OBJECTIVE TEST
1.
The molecular formula of an alkene that contains four carbons atoms is
A.
C4 H4
B.
C4 H6
C.
C4 H8
D.
C4 H10
Answer: C
2.
A flower with both stamens and carpels is said to be
A.
a hermaphrodite.
B.
irregular.
C.
monoecious.
D.
dioecious.
Answer: C
3.
Which of the following quantities is/are measured in joules?
I. Energy
II. Power
III. Work
A.
I only
B.
I and II only
C.
I and III only
D.
I, II and III
Answer: C
4.
Which of the following functions are associated with mammalian skeleton? It...
I. stores calcium and phosphates.
II. protects vial internal organs.
III. produce red blood cells.
IV. stores proteins.
A.
I and II only
B.
III and IV only
C.
I, II, and III only
D.
II, III and IV only
Answer: C
5.
The functional group in methanoic acid is
A.
-O-H
B.
\/C = C/\
C.
-C ≡ C-
D.
-COOH
Answer: D
6.
Which of the following statements about animals are correct?
I. Movement is quick and visible
II. Chloroplast is absent
III. They have thick cellulose cell wall
A.
I and II only
B.
I and III only
C.
II and III only
D.
I, II and III
Answer: A
7.
Organic compounds are mostly
A.
soluble in water.
B.
not inflammable.
C.
covalent.
D.
ionic.
Answer: C
8.
Which of the following plant seeds undergo hypogeal germination?
A.
Cowpea
B.
Flamboyant
C.
Maize
D.
Castor oil
Answer: C
9.
A common disease that affect sheep is
A.
anthrax
B.
aspergillosis
C.
coccidiosis
D.
gumboro
Answer: A
10.
Liming the soil improves its fertility by
A.
neutralizing soil acidity.
B.
decreasing the activity of soil microorganisms.
C.
improving soil structure.
D.
reducing soil erosion.
Answer: A
11.
Which of the following statements about an atoms is correct?
A.
Protons out number electrons in a neutral atom
B.
The L-shell is closest to the nucleus
C.
Neutrons are found in the nucleus
D.
The atomic number is greater than the mass number
Answer: C
12.
A solution of volume 500 cm3 contains 9.80 g 0f H2SO4.
Determine its molar concentration.
[S=32, O=16, H=1]
A.
0.10 M
B.
0.20 M
C.
0.40 M
D.
0.50 M
Answer: B
Molar/Concentration Formula
Molar/Concentration =
Mole =
Molar/Concentration =
Note: volume is in dm3 hence convert the cm3 to dm3 by dividing by 1000
500 cm3 = = 0.5 dm3
Mass = 9.8 g
Molar Mass = 1 x 2 + 32 + 16 x 4 = 98 g mol-1
Molar = = 0.2 M
13.
In a step-down transformer,
A.
there are more turns in the secondary coil than in the primary.
B.
the current in the primary coil is more than the current in the secondary coil.
C.
the voltage of the secondary coil is higher than that of the primary.
D.
there are more turns in the primary coil than in the secondary.
Answer: D
14.
The SI unit of electric charge is
A.
ampere.
B.
coulomb.
C.
ohm.
D.
volt.
Answer: B
15.
The normal period for a human pregnancy is
A.
52 weeks.
B.
32 weeks.
C.
28 weeks
D.
40 weeks
Answer: D
16.
Which of the following groups of characteristics in humans is classified as phenotype?
A.
Eye colour and height
B.
Eye colour and blood group
C.
Height and sickle cell
D.
Blood group and height
Answer: A
17.
The role of oxygen in seed germination is to
A.
provide energy for cell division and growth.
B.
soften the seed coat.
C.
dissolve the stored food.
D.
transport food substances to site of growth.
Answer: A
18.
Smoke is a mixture of
A.
liquid and gas.
B.
gases.
C.
solid and gas.
D.
solid, liquid and gas.
Answer: C
19.
An example of a wind instrument is
A.
xylophone.
B.
guitar.
C.
flute.
D.
cymbals.
Answer: C
20.
The gas in the atmosphere that absorbs ultra violet rays is
A.
carbon(IV) oxide
B.
nitrogen
C.
oxygen
D.
ozone
Answer: D
21.
Water is referred to as universal solvent because it
A.
dissolves most substances.
B.
changes blue litmus solution to red.
C.
reacts with base to produce salt.
D.
has pH of 7.
Answer: A
22.
Which of the following element is constituent of brass?
A.
Iron
B.
Magnesium
C.
Tin
D.
Zinc
Answer: D
An alloy is a substance made by melting two or more elements together, at least one of them metal.
Examples
Steel: the name given to an alloy of iron with carbon, usually with other elements, such as nickel and cobalt. The other elements add a desired quality to the steel, such as hardness or tensile strength.
Stainless Steel: another iron alloy, which typically contains chromium, nickel, and other elements to resist rust or corrosion.
Pewter: an alloy of tin, with other elements such as copper, lead, or antimony. The alloy is malleable, yet stronger than pure tin, plus it resists the phase change of tin that can make it crumble at low temperatures.
Brass: a mixture of copper with zinc and sometimes other elements. Brass is hard and durable, making it suitable for plumbing fixtures and machined parts.
Sterling Silver: is 92.5% silver with copper and other metals. Alloying silver makes it harder and more durable, although the copper tends to lead to greenish-black oxidation (tarnish).
Electrum: Some alloys, like electrum, occur naturally. This alloy of silver and gold was highly prized by ancient man.
Meteoritic Iron: While meteorites may consist of any number of materials, some are natural alloys of iron and nickel, with extraterrestrial origins. These alloys were used by ancient cultures to make weapons and tools.
Amalgams: These are mercury alloys. The mercury makes the alloy much like a paste. Amalgams may be used in dental fillings, with the mercury intact, although another use is to spread the amalgam and then heat it to vaporize the mercury, leaving a coating of another metal.
23.
Which of the following brooder house equipment confines day-old chicks?
A.
Feed trough
B.
Chick guard
C.
Hover
D.
Liter
Answer: B
24.
Which of the following nutrients is not needed by crops in large quantity?
A.
Calcium
B.
Iron
C.
Nitrogen
D.
Phosphorus
Answer: B
25.
The work done by a machine in moving a body is 450 J. If the force applied is 30.0 N, calculate the distance through which the body moved.
A.
1.5 m
B.
1.5 x 10 m
C.
6.7 x 10-2 m
D.
1.35 x 104 m
Answer: B
Work done Formula
Work done = Force x Distance
Distance =
Work done = 450 J
Force = 30.0 N
Distance = = 15 m = 1.5 x 10 m
26.
Which of the following benefits could be derived by a farmer from the practice of mulching?
I. Control of growth of weeds
II. Improvement in soil structure
III. Reduction of soil erosion
A.
I and II only
B.
I and III only
C.
II and III only
D.
I, II and III
Answer: D
27.
Which of the following crops is not a root vegetable?
A.
Carrot
B.
Ginger
C.
Lettuce
D.
Onion
Answer: C
28.
Thinning out means
A.
spacing out seedlings in the nursery.
B.
removing diseased crops from the farm.
C.
spacing out seedlings when planting.
D.
removing extra seedlings from a stand.
Answer: D
29.
Alkanoic acid + alkanol ⇋H2SO4 alkyl alkanoate + water
Use the equation above to answer the question below
The reaction is called
A.
hydrolysis.
B.
hydration.
C.
dehydration.
D.
esterification.
Answer: D
30.
Pruning is a cultural practice undertaken in vegetable production to
A.
provide shade and protection
B.
remove diseased branches and leaves from plant
C.
prevent plants from falling
D.
prevent exposure of plants to rain, wind and sun
Answer: B
31.
Maintenance ration provides farm animals with nutrients required for
A.
egg production.
B.
vital body processes.
C.
growth and development.
D.
development and maturity.
Answer: B
32.
Which of the following substances is a by-product of soap production?
A.
Brine
B.
Ethanol
C.
Fatty acid
D.
Glycerol
Answer: D
33.
The radiation with the highest penetration power is
A.
x-ray
B.
gamma ray
C.
alpha particle
D.
beta particles
Answer: B
34.
Fertilization in flowering plants is known as double because
A.
the female nucleus is double penetrated by one male gamete while the other regenerate
B.
two cotyledons are formed.
C.
two embryo nucleus are formed.
D.
one male gamete fertilizes the egg while the second fuses with the polar nuclei.
Answer: D
35.
The arrangement of electrons in shells of an atom is called
A.
atomic structure
B.
periodic arrangement.
C.
electronic configuration
D.
electronic structure
Answer: C
36.
In crop production, pests and parasites do not cause
A.
increase in yield
B.
total loss of crop
C.
stunted growth
D.
reduced market value
Answer: A
37.
The diagram below illustrates a ray of light incident on a plane mirror MM'.
The value of α is
A.
40°
B.
50°
C.
80°
D.
100°
Answer: B
Angle of incidence (α) equals the angle of reflection (r)
r + 40° = 90° (right angle)
r = 90° - 40°
r = 50°
α = r = 50°
38.
Which of the following organisms transmits the protozoa which causes trypanosomiasis in cattle?
A.
Louse
B.
Mosquito
C.
Tick
D.
Tsetse fly
Answer: D
39.
Exhaled air may readily put off a lighted candle it contains high levels of
A.
carbon dioxide and moisture
B.
oxygen and moisture
C.
nitrogen and heat
D.
oxygen and nitrogen
Answer: A
40.
The potential difference across the terminals of a resistor is 24 V.
Determine the current which will flow through the resistor with resistance 15 Ω.
A.
40.0 A
B.
1.6 A
C.
10.0 A
D.
0.6 A
Answer: B
Voltage Formula
Voltage(V) = Current(I) x Resistance(R)
Current(I) =
Voltage = 24 V
Resistance = 15 Ω
Current(I) = = 1.6 A
41.
Cowpea plants are used in crop rotation system of farming so that
A.
grazing animals would not destroy the crops.
B.
nitrates would be added to the soil.
C.
soil erosion could be checked.
D.
weeds would be suppressed.
Answer: B
42.
The instrument most suitable for the measurement of the thickness of a sheet of paper is
A.
Vernier callipers.
B.
micrometer screw gauge.
C.
metre rule.
D.
engineers callipers.
Answer: B
43.
A substance that contains 10 electrons and 11 protons is
A.
a halogen.
B.
a noble gas.
C.
an ion.
D.
an atom.
Answer: C
In a neutral atom, the number of electrons equals the number of protons. Since the protons (11) are more than the electrons (10), means one (1) electron has been lost/transferred to another to form a cation (an ion).
44.
Ozone layer depletion results in
A.
melting of ice at the poles.
B.
increase in number of storms.
C.
skin cancer in humans.
D.
loss of productive farmland.
Answer: C
Ozone depletion can cause increased amounts of UV radiation to reach the Earth which can lead to more cases of skin cancer, cataracts, and impaired immune systems. Too much exposure to UV is believed to be contributing to the increase in melanoma, the most fatal of all skin cancers.
45.
If the genotype of the parents are Aa and Aa, the offsprint most probably will be
A.
AA and aa.
B.
all Aa.
C.
AA, Aa and aa.
D.
AA and aa.
Answer: C
There are 2 out of 4 (half) Aa , 1 out of 4 of AA and 1 out of 4 of aa
46.
Which of the following statements about sea breeze is/are correct? It
I. occurs during the night.
II. occurs during the day.
III. blows towards the sea.
A.
II only
B.
I and III only
C.
I only
D.
II and III only
Answer: A
47.
An electrical bulb is rated 20W. This means that when it is in use, the
A.
energy required to light it if outages is 20J
B.
amount of energy consumed every second is 20J
C.
word done in a day is 20J
D.
amount of energy consumed every hour is 20J
Answer: B
Power
Power =
The S.I unit for power is W.
The S.I unit for time is second (s)
48.
Rainbow formation is a practical illustration of the light phenomenon known as
A.
dispersion
B.
interference
C.
mirage
D.
reflection
Answer: A
49.
An electrical circuit consists of a 2 V cell connected to a 5 Ω resistor.
Determine the amount of current through the resistor when the circuit is closed.
A.
0.4 A
B.
1.0 A
C.
2.5 A
D.
4.0 A
Answer: A
Voltage Formula
Voltage(V) = Current(I) x Resistance(R)
Current(I) =
Voltage = 2 V
Resistance = 5 Ω
Current(I) = = 0.4 A
50.
Given that the Avogadro's constant is 6.02 x 1023, determine the number of atoms in 0.01 moles of a substance.
A.
6.02 x 1020 atoms
B.
6.02 x 1021 atoms
C.
6.02 x 1023 atoms
D.
6.02 x 1024 atoms
Answer: B
Method I
Number of atoms = Mole x Avogadro's constant
Mole = 0.01 moles
Avogadro's constant = 6.02 x 1023
Number of atoms = 0.01 x 6.02 x 1023
Number of atoms = 6.02 x 1021 atoms
Method II
If 1 mole contains 6.02 x 1023 atoms
0.01 moles will contain 0.01 x 6.02 x 1023 atoms = 6.02 x 1021 atoms
THEORY QUESTIONS
1.
(a)
(i)
Explain each of the following terms as used in maize production:
(α)
supplying;
(β)
thinning.
(ii)
State two diseases that affect maize.
(b)
(i)
Name the two biological systems which help to co-ordinate the body's activities.
(ii)
Mention the two hormones produced by the pancreas.
(iii)
Name one disease condition associated with the failure of the pancreas to produce sufficient hormone.
(c)
Name the type of bond formed when there is a reaction between each of the following pairs of elements:
(i)
Carbon and oxygen;
(ii)
Hydrogen and sulphur;
(iii)
Copper and oxygen;
(iv)
Carbon and hydrogen.
(d)
(i)
Distinguish between permanent magnet and temporary magnet.
(ii)
State:
(α)
two uses of permanent magnets
(β)
one use of temporary magnets
(a)
(i)
(α)
Supplying is the replanting of seeds at the stands where seeds fail to germinate
OR
Supplying is the replacement of ungerminated seed at a stand.
(β)
Thinning is the removal of excess seedlings from a stand.
(ii)
Diseases that affect maize
1. Smut
2. Rust
3. Streak
(b)
(i)
Names of biological systems which help to co-ordinate the body's activities
1. The nervous system
2. The hormonal/endocrine system
(ii)
Hormones produced by the pancreas
1. Insulin
2. Glucagon
3. Pancreatic polypeptide
4. Somatostatin
(iii)
The disease condition associated with the failure of the pancreas to produce sufficient hormone is diabetes.
(c)
Types of bond formed between pairs of elements
(i)
Carbon and oxygen → Covalent bond
(ii)
Hydrogen and sulphur → Covalent bond
(iii)
Copper and oxygen → Ionic/electrovalent
(iv)
Carbon and hydrogen → Covalent bond
(d)
(i)
Distinction between permanent magnet and temporary magnet
| Permanent Magnets | Temporary Magnets |
| They are made from hard magnetic substances | They are made from soft magnetic substances |
| They maintain magnetism for a long period | They possess magnetism only in the presence of a magnetic field |
(ii)
(α)
Uses of permanent magnets
1. To build electric motors or power windows in cars or wind shield wipers
2. In (refrigerator/fridge) doors
3. In electricity generators
4. In cathode ray tubes
5. To separate magnetic material from non-magnetic material
6. In automobile/electric vehicles
7. In air conditioners/washing machines
8. Storage devices (hard drive/pen drive/floppy disk) of computer
9. In electric train/track
10. Television/computers/phones/loud speakers
11. Making of jewellery/bracelets/ear ring/necklaces/beads
12. In compasses
(β)
Uses of temporary magnets
1. As electromagnets
2. To separate materials of iron from scrap metals
2.
(a)
(i)
List three characteristics of ionic compounds.
(ii)
Explain why helium does not form a compound.
(b)
(i)
What is industrial waste?
(ii)
State four ways by which industrial waste could be useful.
(c)
(i)
Explain the term soil fertility.
(ii)
Differentiate between major nutrients and minor nutrients.
(d)
(i)
Differentiate between distance and displacement.
(ii)
A bird flies at a speed of 250 km/h. If it covers a distance of 10,000 m, calculate the time it took to complete the journey.
(a)
(i)
Characteristics of ionic compounds
1. They are solid at room temperature
2. They have high boiling point
3. They have high density
4. They are generally soluble in polar solvents/water
5. They conduct electricity in molten state/in aqueous solution
6. They have high melting point
7. They exist in crystalline form
(ii)
Why helium does not form a compound
1. Helium is an element with completely filled valence shell/it is stable/has maximum of 2 electrons in its shell
2. It therefore does not require transfer (or acceptance or sharing) of valence electrons for stability
(b)
(i)
Industrial waste is solid (or semi-solid or liquid or gaseous) unwanted material from industrial processes or activity.
(ii)
Ways by which industrial waste could be useful
1. Through recycling
2. Recovering waste for re-use
3. Turning industrial waste into manure
4. Channeling waste watr for agricultural use
5. Treating biomass to become biogas for energy
6. Using husks for making door mats
7. Using watr sachets in making bags
8. Using cocoa husks for making soap
9. Generate income
(c)
(i)
Soil fertility refers to a soil that contains the needed crop nutrients (in right quantities) for propere crop growth.
OR
Soil fertility is the ability of the soil to support effctive crop growth.
(ii)
Distinction between major nutrients and minor nutrients
Major nutrients are food/chemical substances needed by crops in large quantities whereas minor nutrients are those food/chemical substances needed in small quantities by crops.
(d)
(i)
Distinction between distance and displacement
| Distance | Displacement |
| Length between two positions | Length between two positions measured in a specified direction |
| A scalar quantity/has magnitude only | A vector quantity/has both magnitude and direction |
| Always taken as positive | Can be positive or negative or zero |
| Changes according to the path taken by the body | Does not depend on its path but depends only on its initial and final positions |
| Distance = Speed x Time | Displacement = Velocity x Time |
| S.I. symbol is d | S.I. symbol is s |
| Does not decrease with time | Decrease with time |
| Gives a complete information of the route followed by the body | Does not give complete information of the route followed by the body |
(ii)
Change the speed from km/h to m/s which is the S.I unit for speed.
Speed = 250 km/h = = 69.4 m/s
Time =
Time = = 144s
3.
(a)
(i)
State the law of floatation.
(ii)
State three characteristics of the image formed by a plane mirror.
(b)
Give one reason for undertaking each of the following practices in animal production:
(i)
providing feed and water in clean containers;
(ii)
ensuring a routine deworming programme;
(iii)
practicing rotational grazing;
(iv)
avoiding overstocking of animals;
(v)
preventing sheep from feeding on wet pastures.
(c)
Write a balanced chemical equation for the reaction between:
(i)
water and sodium;
(ii)
water and magnesium
(d)
State four human activities that contribute to global warming.
(a)
(i)
The law of floatation states that a floating body displaces its own weight of the fluid in which it floats.
(ii)
Characteristics of the image formed by a plane mirror
The image formed by a plane mirror is:
1. upright/erect
2. at equal distance from the mirror as the object
3. virtual/behind the mirror
4. Laterally inverted
5. Equal in size as the object
(b)
(i)
Reason for providing feed and water in clean containers
To avoid contamination
(ii)
Reason for ensuring a routine deworming programme
To prevent worm infestation
(iii)
Reason for practicing rotational grazing
To prevent pest build-up/break the cycle of pest infestation
(iv)
Reasons for avoiding overstocking of animals
1. To prevent fighting or cannibalism
2. To ensure proper spacing
3. To avoid spread of diseases
4. To ensure proper ventilation
(v)
Reasons for preventing sheep from feeding on wet pastures
1. To prevent diarrhoea
2. To prevent infestation by worms
(c)
Balanced chemical equations
(i)
Water and sodium
2Na + 2H2O → 2NaOH + H2
(ii)
Water and magnesium
Mg + 2H2O → Mg(OH)2 + H2
OR
Mg + H2O → MgO + H2
(d)
Human activities that contribute to global warming
1. Burning of fossil fuels/petrol/hydrocarbons/wood/coal/wood products/solid waste
2. Deforestation/cutting down trees/vegetation
3. Industrial activities/fumes from industries
4. Bush/forest fires
5. Emission of exhaust fumes from cars
6. Cooking of food
7. Agricultural activities/breeding of cattle which produce methane
4.
(a)
Outline the path taken by inhaled air beginning from the nostrils to the alveolus.
(b)
(i)
What is the water cycle?
(ii)
State four processes involved in the water cycle.
(c)
List four factors that should be considered in selecting a site for large-scale vegetable production.
(d)
(i)
State three ways of protecting people from the effects of radioactivity.
(ii)
State two uses of nuclear energy.
(a)
The path taken by inhaled air beginning from the nostrils to the alveolus
Nasal cavity/Nostrils
↓
Pharynx
↓
Larynx/voice box
↓
Trachea/windpipe
↓
Bronchi/bronchus
↓
Alveolus
(b)
(i)
Water cycle is a set of natural processes that indicate the repeated use and release of water.
OR
Water cycle is a set of natural processes that describes how water evaporates from the surface of the earth into the atmosphere, cools/condenses into rain or snow in the clouds and falls again to the surface of the earth as rain or precipitation.
(ii)
Processes involved in the water cycle
1. Evaporation (from water sources)
2. Transpiration (from leaves of plants)
3. Respiration (from humans and animals)
4. Cooling/condensation of vapour (to form clouds or drops of water)
5. Sublimation
6. Falling of rain/precipitation/falling of snow
7. Collection into water sources
8. Used by plants/animals (to start the cycle again)
(c)
Factors that should be considered in selecting a site for large-scale vegetable production
1. Type of soil/fertility of soil/pH of soil
2. Topography of the land
3. Nearness to source of water
4. Nearness to market
5. Nearness to farmer's settlement/residence
6. Easy accessibility of the site
7. Availability of labour
8. Cost of preparing/acquiring the land
9. Climatic requirement of the crop
10. The biotic factors/prevalence of pests/diseases
11. Security/political stability
12. Bureaucracy
(d)
(i)
Ways of protecting people from the effects of radioactivity
1. Evacuation of people/resettle people/increasing the distance from radiation source
2. Sheltering in rooms
3. Use of non-radioactive iodine to prevent uptake of radioactive iodine by thyroid gland
4. Keeping radiation detector
5. Educating people
6. Wearing of protective clothing/shield/face mask/respirator
7. Shortening the time of exposure
8. Avoid drinking/eating contaminated water or food
(ii)
Uses of nuclear energy
1. Production of electricity
2. Nuclear medicine/medical uses/human health
3. Heating
4. Space missions
5. Used in agriculture or preservation of food/sterilization of insects/pests or plant mutation/breeding
6. Used in small batteries in exploring space
7. Propulsion of space craft
8. Manufacture of atomic bomb
9. Hydrogen production/fertilizer production
10. In submarines
11. Research
12. Sea water desalination
5.
(a)
(i)
What are alkanoates?
(ii)
State three uses of alkanoates.
(b)
(i)
Explain the term weathering
(ii)
State three ways of maintaining soil fertility on a sloppy land.
(c)
(i)
Give two reasons why genetic variation is important in living organisms.
(ii)
Give three examples of genetic variations in humans.
(d)
(i)
State Archimedes principles
(ii)
A box of volume 200 m3 float on sea water of density 10.30 kgm-3.
Calculate the Upthrust of the sea water on the boat
[g = 10 ms-2]
(a)
(i)
Alkanoates are products formed when an alkanol reacts with an alkanoic acid.
(ii)
Uses of alkanoates
1. Use as perfume, flavoring and essence
2. Use as solvent for paints
3. Use in the production of plastics/polymers
4. Use in making glycerol
(b)
(i)
Weathering is the disintegration and decomposition of rocks into smaller fragment of particles by chemical, physical and biological means.
(ii)
Ways of maintaining soil fertility on a sloppy land
1. Cover cropping
2. Strip Cropping
3. Terracing
4. Countour ploughing
5. Land rotation
(c)
(i)
Reasons why genetic variation is important in living organisms
1. Prevents extinction of species
2. Helps in disease resistance in organism
3. It ensures the survival of the species
(ii)
Examples of genetic variations in humans
1. Skin colour
2. Hair colour
3. Blood type
4. Baldness
5. Sickling
6. Dimples
7. Colour blindness
8. Albinism
9. Height
10. Rhesus factor
(d)
(i)
Archimedes principles states that a body wholly or partially immersed in a fluid experiences an upward force called upthrust which is equal to the weight of fluid displaced.
(ii)
Upthrust = Density x Volume x Acceleration due to gravity
Density = 10.30 kgm-3
Volume = 200 m3
Acceleration due to gravity (g) = 10 ms-2
Upthrust = 10.30 kgm-3 x 200 m3 x 10 ms-2
Upthrust = 20,600 N
6.
(a)
(i)
What is meant by the pole of a magnet?
(ii)
Draw the magnetic lines of force around a bar magnet.
(b)
List four post harvest activities required in the preservation of maize.
(c)
Describe the processes that take place between pollination and seed formation in flowering plants.
(d)
Distinguish beteween:
(i)
an atom and an ion;
(ii)
neutralization and esterification.
(a)
(i)
The pole of a magnet is the part of the magnet where the magnetic force is strongest.
OR
The pole of a magnet is the region of a magnet toward which the lines of magnetic induction converge or diverge.
OR
The pole of a magnet is either of the two ends of a magnet at which the field of the magnet is most intense.
(ii)
The magnetic lines of force around a bar magnet
Note: The direction of arrows is from North to South
(b)
Post harvest activities required in the preservation of maize
1. Dehusking
2. Threshing/shelling
3. Drying
4. Winnowing
5. Treatment with recommended chemical
6. Bagging
7. Storage
(c)
Processes that take place between pollination and seed formation in flowering plants
1. Pollen grain absorbs water/germinates
2. Pollen grain develops/grows into a pollen tube
3. The pollen tube grows through the style and down the wall of the ovary carrying two nuclei (or tube nucleus and generative nucleus)
4. The generative nucleus divides to form two male gametes
5. The pollen tube passes through the micropyle of the ovule into the embryo sac where the tip dissolves setting free male gametes
6. One male fuses/unites with the egg nucleus/ovum to form the zygote which develops into the embryo of the future seed
7. However, the other male gamete fuses with the polar nucleus (or endosperm nucleus) and the fertilized ovule becomes a seed
(d)
(i)
Distinction between an atom and an ion
| Atom | Ion |
| Electrically neutral particle | Charged particle |
| Smallest (indivisible) unit of matter | An atom with an electric charge |
| The number of protons and electrons are the same | The number of protons and electrons are not the same |
| Take part in a chemical reaction | Cannot take part in a chemical reaction/Attract each other by electrostatic force |
(ii)
Distinction between neutralization and esterification
| Neutralization | Esterification |
| Reaction between an acid and a base (to give salt and water only) | Reaction between an organic acid and an alkanol |
| Is exothermic | Is endothermic |
| Is fast/not catalysed | Is slow/requires a catalyst |
| Produces salt and watr only | Produces ester and water |
| Is not reversible | Is reversible |