Study carefully the laboratory devices illustrated below.
(a)
Identify each of the devices A,B,C,D,E,F,G and H.
(b)
Name the parts labelled I, II, III and IV.
(c)
State the use of each of the devices A,B,C,D,E,F,G and H.
(d)
Describe how each of the device A, B, F, G and H is used.
(a)
A → Thermometer
B → Micrometer screw gauge
C → Volumetric or flat bottomed flask
D → Tripod stand
E → Test tube holder
F → (A pair of) tongs
G → Vernier caliper
H → Pipette
I → Bunsen burner
(b)
I → bulb
II → mercury
III → bore or capillary
IV → glass wall or stem
(c)
A (Thermometer) is used to measure temperature or degree of hotness or coldness of a substance.
B (Micrometer screw gauge) is used to measure the thickness or diameter of an object.
C (Flat bottomed flask) is used for measuring or holding (250 ml) of liquid. For preparation of a standard solution or for measuring 250 ml or a known volume of a solution.
D (Tripod stand) is used to support flasks and beakers.
E (Test tube holder) is used for holding test tube during heating.
F (Tongs) is used to hold (hot) objects.
G (Vernier caliper) is used to measure the distance between two opposite sides of a surface.
H (Pipette) is used for drawing solutions or liquids from one container into another or for drawing specific volume of liquids or volumes of liquid.
I (Bunsen burner) is used for heating substances.
(d)
How to use A (Thermometer)
1. Suspend bulb in medium whose temperature is to be determined
2. Allow few minutes for mercury to expand or contract to maximum or minimum level
3. Read off mercury level (against calibrations to give temperature of medium)
How to use B (Micrometer screw gauge)
1. Place the object in the gauge or anvil and spindle or jaws
2. Use the ratchet or thimble to tighten the object (till the ratchet begins to rattle)
3. Add the readings on both the thimble and the sleeve to give thickness of the object
How to use F (Tongs)
1. The thumb is placed in one of the cavities or holes of the handle and another finger placed in the other cavity
2. To open up the device
3. The open end is used to hold the (hot) object
How to use G (Vernier caliper)
1. Object is placed in the jaw
2. The knob is used to slide the jaws to hold the object firmly and the reading is taken through the window on the scale
How to use H (Pipette)
1. The pointer end of the pipette is immersed in the solution
2. The mouth is put at the blunt or opposite end and air sucked from it
3. The liquid level is allowed to rise above the mark and the thumb used to seal the end where the mouth was put
4. The thumb is partially removed to drain some solution or liquid to the mark
5. The thumb is completely removed to allow solution or liquid drain into the appropriate container
PRACTICAL 2
The figure below is an illustration of structures associated with plants.
Study the figure carefully and answer the questions that follow.
(a)
Identify the structures A and B.
(b)
(α)
Name each of the parts labelled I, II, III, IV, V, VI, VII and ,VIII
(β)
State one function of each of the parts labelled II and IV.
(c)
State the relationship between structure A and structure B.
(d)
State the mode of dispersal of the part labelled VIII.
(e)
Name one plant which produces structures similar to B.
(a)
A → Flower
B → Fruit
(b)
(α)
I → Receptable
II → Filament
III → Anther
IV → Style
V → Ovules
VI → Sepal
VII → Pericarp or fruit wall
VIII → Seed
(β)
Function of II (Filament)
It supports the anther or holds the anther in position.
Function of IV (Style)
It connects the stigma to the ovary or helps as passage of the pollen tube into the ovule or holds stigma in position.
(c)
Structure B (fruit) develops from structure A (flower).
(d)
Explosive mechanism
(e)
Plants which produces structures similar to B (fruit)
1. Flamboyant
2. Caesalpinea or pride of Barbados
3. Crotalaria
4. Bean
5. Squirting cucumber
6. Cowpea
7. Balsam
PRACTICAL 3
The figure below is an illustration of fruits of some plant species.
Study the figure carefully and answer the questions that follow.
(a)
In each case name one plant which has fruits similar to those represented in A, B and C.
(b)
Name the agent of dispersal of the seeds of each of the fruits A, B and C.
(c)
Explain the mode of dispersal of seeds of each of the fruits A, B and C.
(d)
State three ways in which dispersal of seeds is important to the plants whose fruits are illustrated above.
(a)
A → Boerhaavia (sp) or pig weed; Desmodium (sp)
B → Tridax (sp); Silk cotton (sp); Tecoma (sp)
C → Acacia (sp); Cassia (sp); Pride of Barbados or Caesalpinea (sp); Crotalaria (sp);Beans or Cowpea
(b)
A → Animal or human
B → Wind
C → self or explosive mechanism
(c)
Fruit A
1. Has sticky hairs which get attached to fur or skin of animal or clothing of human
2. As the animal or human moves along, the fruit may be dislodged and drop at a different location
Fruit B
Has hairs or is light which enable the fruit to float in the air and transported to a different locality.
Fruit C
1. Has margin which is capable of splitting when it dries up or unequal drying of the fruit coat
2. Tension set up in the fruit while it dries or twisting of the pericap
3. Causes seeds to be thrown out as it splits open
(d)
Importance of dispersal of seeds
1. It prevents overcrowding of plants or reduces competition for light and soil nutrients among seedlings
2. It enables plant to grow in new places
3. It reduces the spread of epidemic diseases among crowded seedlings
4. It enhances the survival of the species
5. It prevents intense feeding by herbivorous animal
PRACTICAL 4
Study the diagrams below and answer the questions that follow.
(a)
Identify the diagrams A and B.
(b)
Name the parts labelled I, II, III and IV.
(c)
Tabulate two structural differences between the two types of seeds
(d)
State what would be observed when a drop of iodine is added to the part labelled I in B.
(e)
Give reasons for your answer.
(a)
A → dicotyledonous seed
B → monocotyledonous seed
(b)
I → endosperm
II → plumule
III → testa
IV → plumule
(c)
Structural differences between monocotyledonous and dicotyledonous seeds
A (Dicocotyledonous seed)
B (Monococotyledonous seed)
Two cotyledons
One cotyledon
Pericarp and testa separate
Pericarp and testa fused together
No endosperm
Endosperm present
(d)
Observation when drop of iodine is added to I (endosperm)
It will turn blue black.
(e)
Why iodine turns blue black when added to I (endosperm)
This is because I (endosperm) contains starch
PRACTICAL 5
Describe briefly how each of the following mixtures could be separated:
(a)
iron filings and sand
(b)
crystals of iodine and charcoal
(a)
Separation of iron filings and sand
Magnetic method of separation is used to separate the iron filings and sand.
Magnet is used to attract the iron filings onto it, leaving the sand behind.
(b)
Separation of crystals of iodine and charcoal
Sublimation method of separation is used to separate the crystals of iodine and charcoal.
1. Put the mixture of the crystals of iodine and charcoal into a dish
2. Put an inverted gas funnel over it.
3. Place a cotton plug in its stem
4. Heat the dish. Iodine undergoes sublimation and its vapours get condensed on the inner side of the funnel and cotton plug.
5. Charcoal will remain in the dish
Additional Note
Other substances that sublimes include:
1. Anhydrous aluminium chloride
2. Anhydrous iron (III) chloride
3. Phenyl methanoic acid (benzoic acid)
4. Ammonium chloride
PRACTICAL 6
The time, t taken for the distance x1,x2,x3,x4 and x5 moved by an object from point A to B is shown in the figure below.
Record the corresponding times t1,t2,t3,t4 and t5 in the table below:
Distance x
Time t (s)
Raw values of x (cm)
Converted values of x (m)
(a)
Draw a graph of the converted distance X on the vertical axis against the time t on the horizontal axis.
(b)
Determine the slope of the graph.
(c)
What does the slope represent?
(a)
Distance x
Time t (s)
Raw values of x (cm)
Converted values of x (m)
2.0
10.0
0.5
6.0
30.0
1.5
10.0
50.0
2.5
14.0
70.0
3.5
16.0
80.0
4.0
(b)
Slope/Gradient = =
Slope/Gradient = = = 20 ms-1
(c)
The slope represents velocity or average speed of the object.
PRACTICAL 7
The figure below shows the three dimensional faces of B, C and D of a rectangular block of wood. The block is weighed using a spring balance as shown in the figure.
Use the figure to answer the questions which follow.
(a)
Calculate the area A of each of the surfaces marked B, C and D in metres.
(b)
What is the weight F of the block?
(c)
Calculate the ratio
(i)
for surface B.
(ii)
for surface C.
(iii)
for surface D.
(d)
What does each of the ratios in (iii) above represents?
(e)
What conclusion can you draw from the comparism of the ratios you have calculated in (iii) above
(a)
20 cm = 0.2 m
30 cm = 0.3 m
60 cm = 0.6 m
Area = Length x Breadth
Area for surface B
Area = 0.2 x 0.3
Area = 2 x 10-1 x 3 x -1 Area = 2 x 3 x 10-1+-1 Area = 6 x 10-2m2
Area for surface C
Area = 0.3 x 0.6
Area = 3 x 10-1 x 6 x -1 Area = 3 x 6 x 10-1+-1 Area = 18 x 10-2m2
Area for surface D
Area = 0.2 x 0.6
Area = 2 x 10-1 x 6 x -1 Area = 2 x 6 x 10-1+-1 Area = 12 x 10-2m2
(b)
Weight F = 75N
(c)
Calculate the ratio
(i)
for surface B: = = 12.5 x 102 =1250Nm-2
(ii)
for surface C: = = 4.167 x 102 =416.7Nm-2
(iii)
for surface D: = = 6.25 x 102 =625Nm-2
(d)
The ratios represent pressure
(e)
Pressure decreases when the area (A) of application increases
PRACTICAL 8
The drawings below show two cells A and B from two pieces of onion tissue. Each onion tissue was mounted in either water or salt solution. Use the diagram to answer questions (i) and (ii).
(a)
Which cell was from the tissue mounted in water?
(b)
Describe and explain the appearance of cell B after about 5 minutes.
(a)
Cell A
(b)
Description
The cell will become plasmolysed as the cell will loose water and shrink with the cytoplasm pulling away
Explanation
This is because the cell was placed in a solution which was more concentrated than the cell content. Water from the cell moved from the lower concentration of the cell to the more concentrated solution by means of osmosis.
PRACTICAL 9
(a)
State one use of the following apparatus in the laboratory.
(i)
Fume chamber
(ii)
Volumetric flask
(iii)
Pipette
(iv)
Burette
(b)
What is observed when the following tests are performed in the laboratory?
(i)
A glowing splint is dipped into a test tube containing hydrogen.
(ii)
Hydrogen gas is passed over heated copper (II) oxide.
(iii)
A piece of coloured cloth is lowered in a test-tube containing chlorine.
(iv)
Carbon (IV) oxide gas is passed through lime water for a long time.
(a)
(i)
Fume chamber is used for the preparation of toxic gases or getting rid of dangerous gases.
(ii)
Volumetric flask is used for the preparation of standard solutions or for measure of specific volumes.
(iii)
Pipette is used to take or deliver a known volume of liquid substances.
(iv)
Burette is used for titration or for measuring a known volume of solution.
(b)
(i)
A glowing splint is dipped into a test tube containing hydrogen
A pop sound is heard or the glowing splint is extinguished.
(ii)
Hydrogen gas is passed over heated copper (II) oxide
There is the formation of a brown solid due to the reduction of copper (II) oxide to copper and water is formed.
CuO(s) + H2(g) → Cu(s) + H2O(l)
(iii)
A piece of coloured cloth is lowered in a test-tube containing chlorine
The coloured cloth is decolourised or bleached.
(iv)
Carbon (IV) oxide gas is passed through lime water for a long time
The lime water turns milky and then colourless.
Carbon (IV) oxide (CO2) + Lime water [Ca(OH)2] → Calcium carbonate (CaCO3) + Water (H2O)
PRACTICAL 10
Study the following diagram and answer the questions which follow it.
(a)
Name the parts labelled, I,II,III,IV,V,VI,VII,VIII,IX and X.
(b)
(i)
Which of the parts secretes bile?
(ii)
What is the function of bile?
(c)
(i)
List two enzymes secreted by the part labelled IV.
(ii)
What are the functions of each of the two enzymes you have listed in (c)(i) above?
(iii)
Give one function each of the parts VII and VIII.
(a)
I → Oesophagus or gullet
II → Liver
III → Gall blader
IV → Stomach
V → Pancreas
VI → Duodenum
VII → Ileum or Small intestine
VIII → Large intestine or Colon
IX → Appendix
X → Anus
(b)
(i)
II (Liver) secretes bile
(ii)
The bile emulsifies fat.
(c)
(i)
Enzymes secreted by the part labelled IV (Stomach)
Pepsin and Rennin
(ii)
Pepsin changes protein to peptones.
Rennin coagulates or clots milk protein for the enzyme pepsin to work on it.
(iii)
Function of the part VII (Small intestine)
Final digestion takes place in ileum or absorption of digested food into the blood stream occurs in the ileum.
Function of the part VIII (Large intestine)
The large intestine is for the removal of faeces or for the absorption of water into the blood stream.
PRACTICAL 11
The following apparatus is for the laboratory preparation of oxygen.
(a)
Name the parts labelled I to IV.
(b)
Write down the name(s) of the chemical(s) used in the part labelled IV.
(c)
How would you test for the presence of oxygen produced?
(a)
I → Gas jar
II → Trough or basin
III → Delivery tube
IV → Test tube or boiling tube
(b)
Chemicals for the preparation of oxygen
1. Hydrogen peroxide [H2O2] and Magnesium (IV) oxide [MnO2]
2. Potassium trioxochlorate (V) [KClO3] and Magnesium (IV) oxide [MnO2]
2KClO3 + MnO2(s) → 2KCl(s) + 3O2 + MnO2(s)
The Magnesium (IV) oxide acts as a catalyst.
(c)
Testing for the presence of oxygen
The presence of oxygen is tested for by introducing a glowing splint into a test tube. The glowing splint re-kindles proving the presence of oxygen.
PRACTICAL 12
Name an apparatus you would use in the laboratory to perform the following
(a)
Measure the temperature of boiling water
(b)
Measure electric current
(c)
Hold a test tube during heating
(d)
Vary the resistance in an electric circuit
(e)
Measure the diameter of a wire
(f)
Grind substance into powdry form
(g)
Measure the potential difference between two points in an electric circuit
(h)
Determine the number of living organisms within a given area under ecological study
(a)
Thermometer
(b)
Ammeter
(c)
Test tube holder
(d)
Rheostat
(e)
Micrometer screw gauge
(f)
Mortar and pestle
(g)
Voltmeter
(h)
Quadrant
PRACTICAL 13
The figure below represents the beginning of an experiment to demonstrate a biological principle using yam tissue.
Study the diagram carefully and answer the questions that follow.
(a)
Name the biological principle being demonstrated in this experiment?
(b)
What is the role played by the yam tissue?
(c)
Draw and label a diagram to illustrate what would be observed if the set up is allowed to stand for 24 hours.
(d)
Explain the principle involved in the experiment.
(e)
How would you set up a control of the experiment above?
(f)
Give one example of the biological principle in each of the following living things:
(i)
flowering plants
(ii)
humans
(a)
Osmosis
(b)
A semi-permeable membrane or allows water molecules to pass through.
(c)
(d)
Water moves across the living yam by osmosis into the strong sugar solution that has a high osmotic potential until equilibrium is reached when the concentration of the diluted sugar solution and water are the same.
(e)
Control experiment for demonstration of osmosis in living tissue
1. A trough is filled with distilled water and a living yam cup is placed in it
2. The yam cup is then filled with the distilled water used in filling the trough
3. Since the concentrations on both sides of the yam are the same, there will be no movement of water molecules
(f)
(i)
Examples of osmosis in flowering plants
1. Absorption of water into the root hair
2. Movement of water from cell to cell within the plant
(ii)
Examples of osmosis in humans
1. Selective absorption of water in the kidney
2. Re-absorption of water in the large intestine
3. Absorption of water in the proximal convoluted tubule of a nephron
PRACTICAL 14
(a)
Study the reaction of liquid A with the named substances in the table and complete the inference column.
Experiment
Observation
Inference
i
Liquid A + red litmus
Liquid A + blue litmus
Litmus remained red
Litmus turned red
Liquid is .............
ii
Liquid A + Sodium trioxocarbonate (IV)
Effervescence of colourless gas.
Gas turned lime water milky.
The gas is ..............
iii
Liquid A + Zinc
Bubbles of colourless gas.
The gas burns with "pop" sound.
The gas is ...............
(b)
Name a compound which reacts in a similar way as liquid A.
1. Aqueous solutions of acids are electrolytes, meaning that they conduct electrical current. Some acids are strong electrolytes because they ionize completely in water, yielding a great many ions. Other acids are weak electrolytes that exist primarily in a non-ionized form when dissolved in water.
2. Acids have a sour taste. Lemons, vinegar, and sour candies all contain acids.
3. Acids change the color of certain acid-base indicates. Two common indicators are litmus and phenolphthalein. Blue litmus turns red in the presence of an acid, while phenolphthalein turns colorless.
4. Acids react with active metals to yield hydrogen gas. Recall that an activity series is a list of metals in descending order of reactivity. Metals that are above hydrogen in the activity series will replace the hydrogen from an acid in a single-replacement reaction, as shown below:
Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g) 5. Acids react with bases to produce a salt compound and water. When equal moles of an acid and a base are combined, the acid is neutralized by the base. The products of this reaction are an ionic compound, which is labeled as a salt, and water.
The statement, "They react with calcium carbonate to give a gas" is true as shown in the equation below:
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l) Calcium Carbonate + Hydrochloric acid → Calcium Chloride + Carbon dioxide gas + Water
PRACTICAL 15
The diagram below represent different types of teeth in humans. Use them to answer the questions that follow.
(a)
Identify the diagrams labelled I, II and III.
(b)
State briefly the structural adaptation of each too in relation to diet.
(c)
State one function of each type of teeth labelled I, II and III.
(d)
State two observation differences between the tooth labelled II and III.
(e)
Discuss briefly any four measures employed to ensure proper dental hygiene.
(a)
I → Incisor tooth
II → Canine tooth
III → Cheek took (premolar/molar)
(b)
Structural adaptation of types of teeth
I (Incisor tooth)
The crown is chisel-shaped and it is used for cutting, tearing, gnawing and holding of food.
II (Canine)
The crown is pointed and it is used for stabbing and tearing of flesh.
III (Premolar)
The crown has a large surface area for grinding and crushing of food.
(c)
Functions of types of teeth
I (Incisor tooth) is used for grinding or crushing or chewing
II (Canine) is used for stabbing or tearing or piercing
III (Premolar) is used for cutting or biting
(d)
Differences between the tooth lI (Canine) and III (Premolar)
lI (Canine)
III (Premolar)
Small in size
Large size
Has a single root
Has three roots
(Bluntly) pointed surface or projection or conical
Cusped surface or multiple projection
(e)
Measures to ensure proper dental hygiene
1. Using the teeth for the right purpose
2. Regular brushing of teeth to avoid decay
3. Regular examination of teeth by an expert
4. Intake of refined carbohydrates such as toffees and chocolates must be avoided
5. Eating food rich in vegetables
6. Eating a lot of fruits
7. Eating food rich in calcium
8. Avoid eating too hot or too cold foods
PRACTICAL 16
The density of a piece of stone is determined by first weighing the stone and measuring the volume of the stone.
Use the diagram below to answer the questions that follow.
(a)
What is the mass, M of the stone?
(b)
What is the volume, V1 of the substance in the measuring cylinder in (b)?
(c)
What is the volume, V2 of the substance in the measuring cylinder in (c)?
(d)
Determine the volume, V of water displaced by the stone.
(e)
Calculate the density of the stone.
(a)
M = 85 g
(b)
V1 = 28 cm3
(c)
V2 = 45 cm3
(d)
V = V2 - V1 Volume of stone = 45 cm3 - 28 cm3 = 17 cm3
(e)
Density =
Density of stone = = 5 gcm-3
PRACTICAL 17
(a)
The set-up below is used to test for a gas in the laboratory.
(i)
Name the part labelled I and II.
(ii)
Name the gas that is being tested for
(iii)
Write a balanced equation for the reaction producing the gas you have named in (ii) above.
(iv)
What are you likely to observe in the test tube containing lime water?
(b)
A gas evolved when a mixture of calcium oxide (CaO) and some crystals of ammonium chloride (NH4Cl) were heated in a test tube.
(i)
Name the gas
(ii)
Give two physical properties of the named gas.
(iii)
Write a balanced equation for the reaction that took place.
(c)
Suggest two precautions that should be taken when diluting concentrated tetraoxosulphate (VI) acid with water.
(a)
(i)
I → Cork stopper
II → Delivery tube
(ii)
Carbon dioxide
(iii)
NaHCO3(s) + HCl(aq) → NaCl(aq) + H2O(l) + CO2(g)
(iv)
The lime water turns milky.
(b)
(i)
Ammonia
(ii)
Physical properties of ammonia
1. It is colourless
2. It has a pungent choking smell
(iii)
CaO(s) + 2NH4Cl(s) → 2NH3(g) + CaCl2(s) + H2O(l)
(c)
Precautions when diluting concentrated acid with water
1. The acid should be added to the water slowly and not the other way round.
Note: If water is added to a concentrated acid then the acid may splash out and cause burns and the beaker may also break due to excessive local heating
2. Wearing of plastic gloves to offset heat
3. Eye must be protected by wearing spectables
4. Any spill on the body must be washed quickly
5. Wearing of protective clothing
PRACTICAL 18
(a)
Some hazard symbols usually displayed on chemical containers are listed below:
(i)
What does each symbol signify?
(ii)
Give one name of a chemical which can be associated with each of A,B,C,D and E
(iii)
Name the place where the symbol labelled F is often displayed.
(iv)
Which of the symbol(s) is/are found on chemical containers?
(b)
You are provided with three solutions with pH 2, 7 and 9.
Describe briefly how you would identify the three solutions using red and blue litmus papers.
(a)
(i)
A → Highly inflammable
B → Toxic/poison
C → Irritant/harmful
D → Oxidizing
E → Corrosive
F → No smoking or no naked flame
(ii)
A (Highly inflammable) Chemicals
1. Propanol
2. Ethanol
3. Ether
4. Butanal
5. Petrol or gasoline
6. Liquid nail polish
7. L.P.G.
1. Petrol station or filling station
2. Gas station
3. Petrol tankers
4. Gas tankers
5. Public places or any name public place e.g hospital, hotels etc.
6. Fuel storage areas
When blue litmus paper is dipped in acidic solution, the litmus paper changes its color from blue to red.
When red litmus paper is dipped in the basic solution, the litmus paper changes its color from red to blue.
The neutral solution does not change the color of the litmus paper.
If the colour changes confuse you, remember BAR where the B stands for blue, A stands for acid and R stands for red to mean for acids (A), blue (B) to red (R). Thus Blue Acid Red (BAR).
Once you are able to remember that of the acid, you can reverse the colour change to get that of the basic solution.
PRACTICAL 19
To determine the density of a piece of a wood, a cuboid of it was used. The mass and volume of the cuboid were then determined.
The figure (a) shows the dimensions of the cuboid while (b) shows the cuboid on weighing scale with full scale reading of 1 kg.
(a)
Calculate the volume of the cuboid.
(b)
Read and record the mass, m of the cuboid.
(c)
Calculate the density of the piece of wood.
(a)
Volume of a cuboid = Length x Breadth x Height
Volume of cuboid = 2 x 2.5 x 4 = 20 cm3
(b)
Mass = 85g
(c)
Density =
Density = = 4.25 gcm-3
PRACTICAL 20
(a)
Identify each of the structures A,B and C
(b)
Name each of the parts labelled I,II,III,IV,V,VI and VII
(c)
State one function of each of the parts labelled I, II,V,VI and VII.
(d)
What is the relationship between the structures B and C
(a)
A → Stamen
B → Fruit
C → Seed
(b)
I → Anther
II → Filament
III → Stalk
IV → Sepal
V → Fruit wall
VI → Micropyle
VII → Testa
(c)
Function of I (Anther)
Contain pollen grains.
Function of II (Filament)
Holds anther in position.
Function of V (Fruit wall)
Protects the seeds.
Function of VI (Micropyle)
Water absorbed through during germination. Also helps in respiration and in the exchange of gases.
