Water

Question 1

Water properties (+ function)

Answer 1

• Large LHv (evaporation is effective cooling mechanism)
• High SHC (buffers changes in temperature)
• Metabolite (condensation and hydrolysis reactions)
• Solvent (transport of substances)
• Cohesion (supports columns of water)
• Transparent (photosynthesis under water)
• Ice less dense (habitat for organisms)

Question 2

Water structure

Answer 2

1 atom of oxygen (O) covalently bonded to 2 atoms of hydrogen (H2)

Question 3

How is water a polar molecule?

Answer 3

The shared negative hydrogen electrons are pulled towards the oxygen atom so the other side of each hydrogen atom is has slight positive charge (d+). The unshared negative electrons on the oxygen atom give it a slight negative charge (d-)

Question 4

How do hydrogen bonds form between water molecules?

Answer 4

The slightly negatively charged oxygen atoms attract the slightly positively charged hydrogen atoms of other water molecules

Question 5

How is water a good solvent?

Answer 5

Water is polar so the slightly positively charged end is attracted to the negative ion, and the slightly negatively charged is attracted to the positive ion. This means the ions will get surrounded by water molecules and dissolve

Question 6

How does water have a large LHv?

Answer 6

Takes lots of energy to break the hydrogen bonds between water molecules, so lots of energy is used up when water evaporates

Question 7

How does water have a high SHC?

Answer 7

Lots of the heat energy is used to break the hydrogen bonds between the water molecules, so there is less heat energy available to actually increase the temperature of the water