3.1.7 Water

Question 1

What is the structure and bonding of water?

Answer 1

Two atoms of hydrogen and one atom of oxygen
Dipolar molecule
Hydrogen = positive, oxygen = negative
Hydrogen bonding is the attractive force between molecules
Covalently bonded so don’t conduct electricity

Question 2

What are the properties of water which aid life? (No explanation)

Answer 2

Dipolar
Has hydrogen bonding
Covalently bonded
High boiling point due to hydrogen bonding
High specific heat capacity
High latent heat of vaporisation
Cohesion
Not easily compressed
Transparent

Question 3

How do the properties of water aid life?

Answer 3

High boiling point: buffer against sudden temperature changes
High latent heat of vaporisation: sweating provides an effective cooling effect
Cohesion: xylem can transport water
Not easily compressed: provides support for organisms
Transparent: light can reach aquatic plants

Question 4

How is water used in the metabolism?

Answer 4

Used to break down many complex molecules by hydrolysis
Chemical reactions take place in an aqueous medium
Water is a major raw material in photosynthesis

Question 5

How is water used as a solvent?

Answer 5

It readily dissolves some substances including: gases, wastes, inorganic ions, small hydrophilic molecules and enzymes