Chapter 6 Water

Question 1

why is water is necessary for humans to function?

Answer 1

excretion, digestion, blood circulation, regulation of the body temperature

Question 2

Water is life: what is waters purpose?

Answer 2

Agriculture activity, cooling agent for industry and power generation

Question 3

what are the properties of water?

Answer 3

• colourless, tasteless, odourless
• freezing point : 0
• water changes its state when it absorbs and releases heat
• produce capillary action
• boiling point : 100

Question 4

what changes will water have when impurities are added?

Answer 4

it changes the taste, smell, colour, etc.

Question 5

what changes are made to the water when salt is added?

Answer 5

it lowers the freezing point and increases the boiling point (adding salt increases the density)

Question 6

explain surface tension

Answer 6

water particles below the surface are pulled together equally in all directions but the water particles at the surface do not have any water molecules above them. this makes the water particles strengthen the attractive forces in another direction

Question 7

what is capillary action?

Answer 7

its the process when liquids move up through a solid support

Question 8

what is cohesive force and adhesive force?

Answer 8

cohesive forces: forces between water molecules
adhesive: forces between water molecules and the surface as they come in contact with (unable water to be drawn up against gravity)

Question 9

what are the two types of hydrated compounds?

Answer 9

anhydrous copper (II) sulphate and anhydrous cobalt (II) chloride

Question 10

whats the initial and after colours of the hydrated compounds?

Answer 10

anhydrous copper (II) sulphate: white to blue
anhydrous cobalt (II) chloride: blue to pink

Question 11

what is can the hydrated compounds be used for?

Answer 11

it can be used as an indicator for humidity and the presence of water

Question 12

how to determine the water quality?

Answer 12

• observe its colour, odour and turbidity

- testing for acidity using pH indicator

Question 13

what is the water cycle as known as?

Answer 13

hydrological cycle

Question 14

what is the process of the water cycle?

Answer 14

water travels from the earth surface to the atmosphere and then back to the ground again

Question 15

what are the six steps of the water cycle?

Answer 15

1. evaporation
2. transpiration
3. condensation
4. precipitation
5. surface runoff
6. infiltration and percolation

Question 16

why is the water cycle important?

Answer 16

it ensures the availability of water for all living organisms.
( if did not naturally recycle itself, we would run out of clean water, which is essential to life )

Question 17

water cycle effects

Answer 17

• change the surrounding temperature and regulates the weather patterns
• help in conversion of rocks to soil and circulates important minerals
• creates geological features (eg. ice caps of rivers)
• renews the water in different water bodies and also provides energy (eg. wind energy & hydro energy)

Question 18

READ PG 94

Answer 18

6.5 SUCROSES OF FRESHWATER

Question 19

what are the 6 reasons for the worldwide water crisis?

Answer 19

1. increasing world population
2. urbanization
3. increased water pollution
4. global climate change
5. overuse in agriculture
6. water wastage

Question 20

what are the challenges are we facing due to the worldwide water crisis?

Answer 20

how to effectively conserve, manage and distribute water

Question 21

what is currently the leading seawater desalination solution?

Answer 21

Reverse osmosis

Question 22

what is the difference between water treatment and water purification?

Answer 22

water treatment: make water usable for domestic, industrial, medical etc purposes. remove contaminants for safer usage

water purification: removal of contaminants from untreated water to produce drinking water. removes bacteria, algae, fungi, minerals and made pollutants

Question 23

what are the main 4 steps in water purification?

Answer 23

1. coagulation
2. sedimentation
3. filtration
4. disinfection

Question 24

read pg 96 AND 97

Answer 24

the process of water purification