Topic 2.2 (water H bonding)

Question 1

Why is water a polar molecule?

Answer 1

Because the oxygen nucleus is bigger than the hydrogen nucleus (more protons in oxygen nucleus) electrons are closer to oxygen nucleus, making the oxygen slightly negative and hydrogen slightly positive

Question 2

How does water bond?

Answer 2

Because the O is δ-, and the H is δ+, the slightly positive H can bond to the slightly negative O

Question 3

What are the 6 properties of hydrogen bonding in water

Answer 3

-high surface tension
(Cohesion between molecules = columns flow together and surface can be used as a habitat)

-water freezes at lower density than liquid (ice floats)

-high specific heat capacity (amount of energy required to raise the temp of 1kg= liquid over a wide range of temps for habitat, drink, temperature buffer

-high latent heat of vaporisation (lots of energy transferred from vaporisation surface= a coolant)

-interacts with other polar substances/ ionic substances =transport medium

-a metabolite in reactions eg hydrolysis, photosynthesis