1. S1 Science ETV – Unit 5 – The Wonderful Solvent - Water

2. 1. A person needs about _______ of purified drinking water daily. 100 litres 120 litres 150 litres 180 litres

3. 2. According to the water supply department, drinking water in a modern city should be (I), (II) and (III) only (I), (II) and (IV) only (I), (II), (IV) and (V) only (I), (II), (III), (IV) and (V) only (I) clear (II) bacteria free (III) free from heavy metal (IV) odorless (V) awesome

4. 3. Why river water is not good for drinking? (I), (II) and (III) only (I), (II) and (IV) only (I), (II), (III) and (IV) only (I), (II), (III), (IV) and (V). (I) It may contain sand. (II) It may contain solid particles. (III) It may contain bacteria and micro-organisms. (IV) It may contain organic and inorganic substances (V) It may contain heavy metals

5. 4. Which of the following matching about the tests for water quality is not correct? Gas chromatography – determine the amount of solid impurities in water Atomic absorption spectrometer – determine the amount of heavy metals in water Titration - measure the hardness of water Membrane filtration - estimate the amount of E. Coli in water

6. 5. In 1892, lots of citizens in city Hamburg of Germany suffered from sore belly and died. It was because they did not _____________before drinking. boil the water settle the sediment of water filter the water add chlorine into water

7. 6. The cause of death among people in Hamburg in 1892 was because they suffered from Typhoid Cholera Dysentery Smallpox

8. 7. It is good to keep natural water in reservoirs. Why? (I) and (II) only (I) and (III) only (I), (II) and (III) only (I), (II), (III) and (IV). (I) It allows particles in water to settle. (II) It allows aeration of water. (III) Direct sunlight helps purification of water. (IV) Heavy metals in water can be removed.

9. 8. The largest water treatment works of Hong Kong is located at Eastern district Tuen Mun Shatin Tsuen Wan

10. 9. Large solid particles in raw water will settle at the bottom of ___________. Clarifier Filtration tank Clean water tank Mixing chamber

11. 10. Which of the followings are the sources of raw water? (I), (II) and (III) only (I), (II) and (IV) only (I), (II),(III) and (IV) only (I), (II), (III), (IV) and (V) (I) Dong Jiang river (II) High Island Reservoir (III) Plover Cove Reservoir (IV) Lower Shing Mun Reservoir (V) Many upland catchment areas

12. 11. Which of the following substances are added to raw water before it enter the clarifier? (I) and (II) only (II) and (III) only (I), (II) and (III) only (I), (II), (III) and (IV) (I)hydrated lime (II)alum (III)chlorine (IV)fluoride

13. 12.What is the function of adding hydrated lime solution into raw water? It helps suspended particles to coagulate into large lumps. Regulate the pH level of raw water. Kill the bacteria and algae in water. Remove the odor of raw water.

14. 13. Which of the following substance has function similar to poly-electrolyte? Hydrated lime solution Alum Chlorine Fluoride

15. 14.From the top downward, the correct sequence of layers of material in the filter bed is Gravel  anthracite  sand Anthracite  sand  gravel Anthracite  boulder  gravel Sand  boulder  gravel

16. 15. Which of the following substances are added into filtered water? (I) and (II) only (II) and (III) only (I), (III) and (IV) only (I), (II), (III) and (IV) (I) hydrated lime solution (II) alum (III) chlorine (IV) fluoride