Water

Question 1

Which element in water attracts the electron in the dipole?

Answer 1

oxygen, making it slightly negative and leaving the hydrogen slightly positive

Question 2

What is the bond angle in a water molecule?

Answer 2

104.5

Question 3

What is the name of the bonds that form between water molecules?

Answer 3

hydrogen bonds

Question 4

What is the strength of hydrogen bonds?

Answer 4

• they are weak, when there are few, so they are constantly breaking and reforming
• however, when there are large numbers present they form a strong structure

Question 5

Name 6 properties of water as a result of hydrogen bonding

Answer 5

• excellent solvent
• high specific heat capacity
• high latent heat of vaporisation
• water is less dense when a solid
• high surface tension and cohesion
• acts as a reagent

Question 6

What is the specific heat capacity of water?

Answer 6

4200 J/kg degrees C

Question 7

Why does water have a high specific heat capacity?

Answer 7

takes a lot of energy to break and build all the hydrogen bonds so the temperature of water does not fluctuate greatly

Question 8

What are the advantages of water having a high specific heat capacity?

Answer 8

• provides suitable habitats
• able to maintain constant temperature (able to absorb a lot of heat without huge temperature fluctuations)
• vital for maintaining optimal temperatures for enzyme activity

Question 9

Why does water have a high latent heat of vaporisation?

Answer 9

In order to change state (from liquid to gas) a large amount of thermal energy must be absorbed by water to break the hydrogen bonds and evaporate.

Question 10

Why is water having a high latent heat of vaporisation an advantage?

Answer 10

as only a little water is required to evaporate for the organism to lose a great amount of heat

Question 11

What does cohesion between water molecules allow?

Answer 11

• it allows columns of water to move through the xylem of plants and through blood vessels in animals
• enables surface tension where a body of water meets air

Question 12

What is it called when water molecules are able to make hydrogen bonds with other molecules?

Answer 12

adhesion

Question 13

What does adhesion between water molecules and other molecules allow?

Answer 13

enables water to move up the xylem due to transpiration

Question 14

How is water being a liquid an advantage?

Answer 14

• provides habitats for aquatic organisms
• medium for chemical reactions
• used for transport

Question 15

How is water an important metabolite?

Answer 15

it is used in hydrolysis and condensation reactions

Question 16

How is water a good reaction medium?

Answer 16

the cytoplasm in cells is an aqueous solution where many chemical reactions happen

Question 17

How is water being incompressible an advantage?

Answer 17

It can prevent plants from wilting and act as a hydrostatic skeleton for invertebrates