3.2 water

Question 1

what are the 6 characteristics of water?

Answer 1

1. high specific capacity
2. high latent heat of evaporation
3. very cohesive
   5.good solvent
   6.less dense when solid

Question 2

what are the 4 roles that relate to the properties of
water

Answer 2

• solvent
• transport medium
• coolant
• habitat

Question 3

define a polar molecule

Answer 3

A polar molecule is a molecule in which one end of the molecule is slightly positive, while the other end is slightly negative.

Question 4

give 5 of water functions

what makes water vital to life

Answer 4

1. reactant- in lots of important reactions eg.hydrolysis
2. solvent-most biological reaction take place in solution (cytoplasm)
3. transport medium- solvent properities mean it can transport eg. glucose and o2 around plants and animals
4. temprature control-due to the high specific heat capacity
5. habitat- organisms can survive and reproduce in it

Question 5

What makes water very cohesive?

attrction between water molecules

Answer 5

helps water to flow, helps to transport substances and helps water to transport up plant stems in the transpiration stream

Question 6

What makes water a good

Solvent?

Answer 6

it can dissolve ions eg na+ cl- (salt)
beacuse the delta + part of the water molecule can encapsulate the anion because its attracted to the - charge and the delta - part of water can form a hydration shell around the cation.
Eg. salt around the body via the blood

Question 7

What makes

ice less dense than (l)water

Answer 7

water molecules freeze in a lattice (where each molecule froms 4 H-bonds) that holds the molecules further apart than in liquid state
this makes ice less dense so it floats
this is useful for organisms in cold tempratures becuase the ice insulates the water below preventing it from freezing.

Question 8

What gives water a

high specific heat capacity

energy needed to raise 1g of a substance by 1.c

Answer 8

the H-bonds absorb a lot of energy so it takes longer to heat up

this means water dosent experience rapid temp changes wich makes its a more stable habitat

Question 9

What gives water a

high latent heat of evaporisation

a lot of energy is needed to evaporate water

Answer 9

it takes a lot of energy (heat) to break the H-bonds between molecules

This acts as a coolant eg mamal sweat

Question 10

Which property makes water a good

coolant

Answer 10

high latent heat of evaporation

Question 11

What makes water a good

Solvent?

Answer 11

polar propertie alows it to form hydration shells around ions to dissolve ionic molecules

Question 12

what makes water a good

habitat?

Answer 12

high specific heat capacity and its less dense as ice than liquid