Transcript Purifying Water

S1 Science ETV – Unit 5 – The Wonderful Solvent - Water
1. A person needs about _______ of purified drinking
water daily.
100 litres
120 litres
150 litres
180 litres
2. According to the water supply department, drinking
water in a modern city should be
(I) clear
(II) bacteria free
(III) free from
heavy metal
(IV) odorless
(V) awesome
(I), (II) and (III) only
(I), (II) and (IV) only
(I), (II), (IV) and (V) only
(I), (II), (III), (IV) and (V) only
3. Why river water is not good for drinking?
(I) It may contain sand.
(I), (II) and (III) only
(II) It may contain solid
particles.
(III) It may contain bacteria
and micro-organisms.
(I), (II) and (IV) only
(IV) It may contain organic
and inorganic substances
(V) It may contain heavy
(I), (II), (III) and (IV) only
metals
(I), (II), (III), (IV) and (V).
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
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
6. The cause of death among people in Hamburg in 1892
was because they suffered from
Typhoid
Cholera
Dysentery
Smallpox
7. It is good to keep natural water in reservoirs. Why?
(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.
(I) and (II) only
(I) and (III) only
(I), (II) and (III) only
(I), (II), (III) and (IV).
8. The largest water treatment works of Hong
Kong is located at
Eastern district
Tuen Mun
Shatin
Tsuen Wan
9. Large solid particles in raw water will settle at the
bottom of ___________.
Clarifier
Filtration tank
Clean water tank
Mixing chamber
10. Which of the followings are the sources of raw water?
(I) Dong Jiang river
(I), (II) and (III) only
(II) High Island Reservoir
(III) Plover Cove Reservoir
(IV) Lower Shing Mun
(I), (II) and (IV) only
Reservoir
(V) Many upland
catchment areas
(I), (II),(III) and (IV) only
(I), (II), (III), (IV) and (V)
11. Which of the following substances are added to raw
water before it enter the clarifier?
(I)
(II)
(III)
(IV)
hydrated lime
alum
chlorine
fluoride
(I) and (II) only
(II) and (III) only
(I), (II) and (III) only
(I), (II), (III) and (IV)
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.
13. Which of the following substance has function
similar to poly-electrolyte?
Hydrated lime solution
Alum
Chlorine
Fluoride
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
15. Which of the following substances are added into
filtered water?
(I) hydrated lime solution
(II) alum
(III) chlorine
(IV) fluoride
(I) and (II) only
(II) and (III) only
(I), (III) and (IV) only
(I), (II), (III) and (IV)