i)

Practices that destroy waterbodies

1. Deforestation/clearing vegetation along the river banks
2. Bush burning
3. Farming near water bodies
4. Galamsey/surface mining activities
5. Dumping of solid/liquid waste into water bodies
6. Use of chemicals for fishing
7. Excessive use of chemical fertilizers
8. Defecation into water bodies, etc.

ii)

Methods of conserving water bodies

1. Use of organic materials for composting
2. Use of appropriate methods of fishing
3. Education on effects of galamsey activities
4. Education on defecation into water bodies
5. Use of erosion-control methods in farming
6. Afforestation, etc.

(i)

Elements that combine to form water

1. Hydrogen
2. Oxygen

(ii)

2H₂ + O₂ → 2H₂O

OR

H₂ + $\frac{1}{2}$O₂ → H₂O

i)

Properties of water in terms of odour

Water is odourless

ii)

Properties of water in terms of taste

Water is tasteless

iii)

Properties of water in terms of effect on litmus

Water is neutral to litmus

OR

Water does not change blue or red litmus paper

OR

Water has no effect on litmus paper

i)

Examples of hard water

1. Well water
2. Sea water/lagoon water
3. Borehole

ii)

Why it is advisable to drink hard water

1. It contains ions of calcium which are good for strong bones and teeth
2. It helps to reduce heart ailments

(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)

Hard water is water that does not form lather easily with soap.

OR

Hard water is water that contains Ca ions (Ca²⁺) and Mg ions (Mg²⁺)

(ii)

Ways by which hard water can be made soft

1. Addition of washing soda/sodium carbonate (Na₂CO₃)
2. Boiling
3. Distillation
4. Deionization/use of ion exchange resin

(i)

Is the case with which water can lather with soap or the amount of dissolved Ca/Mg/Fe(II) ion in water.

(ii)

Natural sources of hard and soft water

i)

Physical properties of water

1. Odourless
2. Colourless
3. Tasteless/insipid
4. Freezes at 0^oC
5. Boils at 100^oC
6. Universal solvent
7. Exists in three states
8. Has a density of 1g/cm³ (at 4^oC)
9. It is transparent
10. It has a neutral pH or pH = 7
11. High surface tension
12. It expands anomalously/irregularly

ii)

Why water is neutral

When red litmus paper or blue litmus paper is dropped in a sample of water, there is no change in colour.

i)

Properties of water

1. Made up of hydrogen and oxygen
2. Tasteless/insipid
3. Odourless
4. Boils point at 100^oC
5. Density: 1,000 kg/m³ or 1g/cm³
6. Colourless
7. Freezes at 0^oC
8. A universal solvent
9. Neutral/pH 7
10. Exist as solid,liquid and gas
11. Polar
12. Expands anomalously/irregularly

ii)

Why clothes are washed with soft water

1. Use less soap
2. Clothes remain soft
3. Will be able to completely rinse the soap out of the clothes
4. Clothes keep their colour/brightness

i)

Soft water is water that lathers easily/readilt with soap/water which does not contain/contains negligible Ca²⁺/Mg²⁺/Ca/Mg ions/salt

ii)

Hard water is water that does not lather easily/readily with soap/water which contains Ca²⁺/Mg²⁺/Ca/Mg ions/salt