Water

Question 1

Give 5 properties of water

Answer 1

1. Metabolite
2. Solvent
3. High latent heat of vaporisation
4. High specific heat capacity
5. Cohesive

Question 2

What is the structure of water?

Answer 2

One atom of oxygen joined to two atoms of hydrogen by shared electrons

Question 3

Oxygen is a polar molecule, explain

Answer 3

The shared negative H electrons are pulled towards the O atom, the other side of the H atom is left with a slight positive charge. The unshared negative electrons on the O atom are left with a slight negative charge

Question 4

Explain hydrogen bonding in water

Answer 4

The slightly negatively-charged oxygen atoms attract the slight positively-charged hydrogen atoms of other water molecules. This attraction is hydrogen bonding

Question 5

Water is a metabolite, explain

Answer 5

Many metabolic reactions involve a condensation or hydrolysis reaction. A hydrolysis reaction requires a molecule of water to break a bond. A condensation reaction releases a molecule of water as a new bond is formed

Question 6

Water has a high latent heat of vaporisation, explain

Answer 6

It takes a lot of energy (heat) to break the H bonds between water molecules - a lot of energy is used up when water evaporates. This is useful for cooling down organisms because it means they can use water loss through evaporation to cool down

Question 7

Water has a high specific heat capacity, explain

Answer 7

The H bonds between water molecules can absorb a lot of energy. This is useful as it means that water doesn’t experience rapid changes in temperature

Question 8

Water is a good solvent, explain

Answer 8

A lot of substances in metabolic reactions are ionic - made from positively and negatively charge molecules. Because water is polar, the +ve end of a water molecule will be attracted to the -ve ion, and the -ve end of the water molecule will be attracted to the +ve ion. The ion will become totally surrounded by water molecules - it’ll dissolve

Question 9

Water is cohesive, explain

Answer 9

Water molecules are cohesive because they’re polar. Strong cohesion helps water to flow, making it great at transporting substances. Strong cohesion also means that water has a high surface tension when it comes into contact with air.

Question 10

What is cohesion?

Answer 10

Cohesion is the attraction between molecules of the same type