Water

Question 1

What are water’s 7 properties?

Answer 1

• High specific heat capacity
• high latent heat of evaporation
• solvent
• density
• surface tension
• transparency
• cohesion

Question 2

High specific heat capacity

Answer 2

• water has lots of hydrogen bonds meaning a lot of energy is needed to break them. It means there is less energy available to actually raise the temperature of the water.
• organisms that live in the water can maintain a relatively constant temperature as large bodies of water can maintain a relatively constant temperature.

Question 3

High latent heat of evaporation

Answer 3

• molecules in water are held together by hydrogen bonds meaning a lot of energy is needed to break them allowing it to be a liquid at room temperature.
• water molecules take away a lot of heat energy when it evaporates so it can help cool living things down by sweating.

Question 4

Solvent

Answer 4

• water is polar, the positive and negative parts of the water molecule are attracted to the negative and positive parts of the solute. This means the ions will get totally surrounded by the water molecules - so they dissolve.
• living organisms can take up useful substances such as mineral ions dissolved in water and these dissolved substances can be transported around the organisms body.

Question 5

Density

Answer 5

• water molecules are held further apart in ice than they are in liquid water so ice is less dense than water.
• ice forms an insulating layer on top of the water so the water below doesn’t freeze and aquatic organisms have a stable environment to live in.

Question 6

Surface Tension

Answer 6

• water molecules at the surface are all hydrogen bonded to molecules beneath them meaning that the surface of the water contracts because it is being pulled inwards and gives the surface of water an ability to resist the force that is applied to it.
• it allows columns of water in plant vascular tissues to be pulled up to form roots.
• insects like pond skaters can walk on water due to surface tension.

Question 7

Transparency

Answer 7

• it allows light to go through and act as a starting point for photosynthesis

Question 8

Cohesion

Answer 8

• it is the attraction between molecules of the same type.
• water molecules are very cohesive as they are polar
• water being cohesive helps water to flow making it great for transporting substances (so it can act as a medium)

Question 9

Polar

Answer 9

• shared hydrogen electrons are pulled towards the oxygen atom leaving the other side of each hydrogen atom with a slightly positive charge
• unshared negative electrons on the oxygen atom give it a slightly negative charge
• this makes water a polar molecule