(i)

1. The level of water decreases and the level of the red liquid rises
2. Red liquid moves/diffuses into the water

(ii)

1. Water is at a higher potential/level/pressure so it moves in the direction of lower potential/level/pressure
2. Molecules of red liquid at a higher concentration moves towards region of lower concentration/molecules of red liquid diffuse into the water

(iii)

1. The level of the liquids will be the same/motion of the liquids stop (greater than 10 cm but lower than 30 cm) because the same pressure will be exerted by the liquids in A and B
2. The colour of the liquid in A and B will be uniform/same (pale/light red) because the concentration will be the same

(i)

a → ammonia gas
b → gas jar
c → round bottomed flask

(ii)

The meaning of the arrow sign d is heating

(iii)

The calcium oxide dries the gas produced

(iv)

c is tilted downwards to prevent condensed water from falling back into the hot flask/to cause cracking

(v)

Upward delivery/downward displacement of air

(vi)

Test for the ammonia gas

Damp/moist red litmus paper turns blue in the presence of the (ammonia) gas

OR

Gas produces fumes with HCl vapour/concentrated hydrochloric acid

OR

Gas has pungent/choky/urinal smell

(vii)

1. Calcium hydroxide (Ca(OH)₂)/Sodium hydroxide (NaOH)

2. Ammonium chloride/Ammonium salt (NH₄Cl)

(i)

I → to kill cells/stop photosynthetic process
II → to remove green pigment/decolourized
III → to wash off the alcohol/to soften the leaf

(ii)

The green part turns blue-black because photosynthesis took place in the green part to produce starch

(iii)

The other (yellow) part of the leaf not change colour because it does not contain chlorophyll/green pigment which will trap sunlight for photosynthesis to occur

(iv)

Presence of chlorophyll/green pigment in leaf is required/necessary for photosynthesis/production of starch to take place/occur

(i)

Differences between an opaque object and a translucent object

(ii)

Examples of opaque objects

1. Mirror
2. Wood
3. Metal
4. Wall
5. Human body

Examples of translucent objects

1. Frosted glass
2. Cloth
3. Water
4. Patchment
5. Oil
6. Kerosene spot on paper
7. Lamp shade/cloth/paper

(i)

Importance of seed dispersal

1. It prevents overcrowding of plants/prevents competition among plants for food and sunlight
2. It introduces/spreads plants to new areas
3. It minimizes the spreading of diseases among plants

(ii)

Types of fruits and their mode of dispersal

(i)

Recycling is the production of new products from used/waste materials

OR

Recycling is the conversion of waste materials into useful products.

(ii)

Advantages of recycling of materials

1. It reduces waste in the environment/helps to control pollution
2. It conserves resources
3. It helps to generate income/employment
4. It helps in generation/conversion of energy

(iii)

Recycled products in Ghana

1. Polythene bags
2. Slippers
3. Paper
4. Tissue paper
5. Particle boards
6. Cooking pots
7. Iron rods
8. Rubbers
9. Biogas

(i)

Bedwetting is the unconscious release of urine while asleep.

(ii)

Diseases that may result from bedwetting

1. Skin rashes
2. Yaws
3. Eczema
4. Sores

(i)

Hard water is water that does not lather easily with soap while impure water contains other dissolved substances/foreign materials/bacteria and not good for human consumption.

(ii)

Stages involved in the treatment of water for a community

1. Filtration by passing water through gravel beds
2. Sedimentation by adding alum
3. Chlorination by adding chlorine (to kill germs)
4. Aeration by exposing water to air to remove odour/improve taste
5. Storage and/or distribution

(i)

Density = $\frac{\mathrm{Mass}}{\mathrm{Volume}}$

Volume = Final volume - Initial volume

Volume = 90 cm³ - 60 cm³
Volume = 30.0 cm³

Density = $\frac{\mathrm{36.0\; g}}{30.0{cm}^3}$

Density = 1.2 gcm^-3

(ii)

The stone will float in the liquid because the density of the stone is less than that of the liquid.

(i)

Echo is the reflection of sound from a hard surface

OR

Echo is the sound heard which is a reproduction of the original sound made after reflection from a hard surface.

(ii)

Uses of echoes

1. Used to determine the depth of the seabed/river
2. Used by ships to detect barriers/obstacles at night
3. Used by bats to avoid flying into obstacles
4. Used to determine velocity of sound in air
5. Used to determine position/locate shoals of fish in water
6. Used in ultra sound equipment in hospitals for clinical diagnosis
7. Used in exploration of minerals beneath the earth

(i & ii)

Diseases that affect the respiratory system of human and their preventions

1. Pneumonia

Prevention

1. Covering the chest properly in cold weather
2. Not sleeping in drought conditions such as under a fan, in an open

2. Tuberculosis

Prevention

1. Avoid breathing in dust
2. Avoid smoking
3. Avoiding contact with TB patients

3. Cough

Prevention

1. Avoid eating cold foods
2. Warm food before eating

4. Asthma

Prevention

Avoid pollen dust,fur of animals and other substances that trigger allergic reactions

5. Influenza (flu)

Prevention

1. Avoid contact with infected persons
2. Wash hands frequently

6. Bronchitis

Prevention

Avoid exposure to cold

7. Whooping cough

Prevention

Use vaccine

8. Common cold

Prevention

Avoid inhaling dust particles

9. Lung cancer

Prevention

Avoid smoking

(i)

Biotechnology is the application of biological processes for the benefit of mankind.

OR

Biotechnology is the use of living organisms/micro organisms to produce useful products.

(ii)

Products that are obtained from biotechnology

1. Antibiotic drugs/streptomycin/penicillin
2. Yoghurt/cheese/butter/bread/corn
3. Bear/wine/pito/palm wine/alcoholic beverages
4. Fermentation products such as drinks, foods and food supplements
5. Biogas

(i)

Pressure is the force acting perpendicularly/normally over certain surface

OR

Pressure is the force acting perpendicularly/normally per unit area

Pressure (P) = $\frac{\mathrm{Force\; (F)}}{\mathrm{Area\; (A)}}$

(ii)

Applications of pressure in everyday life

1. Opening a tin of milk with a nail
2. Braking system of a vehicle
3. Pumping bicycle/vehicle tyres with inflator
4. Using syrings to draw medicine
5. Pumping of water from a borehole
6. Hydraulic jack/press
7. Using straw

(i)

Compound is a substance which contains two or more elements chemically combined.

(ii)

Properties of a compound

1. New substance formed with property different from any of the constituents
2. Substance formed cannot be broken down to obtain the reactants by any physical means
3. Compounds contain their constituents in one fixed proportion/composition/ratio
4. Their formation involves heat exchanges

(iii)