1.7-8 Water & Inorganic Ions

Question 1

What bonding does water use?

Answer 1

Covalent bonding

Therefore has areas of positivity and negativity

Question 2

What is special about water?

Answer 2

It’s the only substance found in all 3 states naturally

Question 3

What kind of molecule is water?

Answer 3

It’s a polar molecule

Question 4

What intermolecular forces are formed between water molecules? Strong or weak?

Answer 4

Hydrogen bonding

Strongest intermolecular forces

Question 5

What are some properties of water?

Answer 5

Dipolar molecule
Hydrogen bonding 
A metabolite in metabolic reactions
A solvent
Cohesive and adhesive 
High latent heat of vaporisation 
High specific heat capacity

Question 6

What is metabolite?

Answer 6

It takes part and is necessary in metabolic reactions

Question 7

What are some examples where water is a metabolite?

Answer 7

Hydrolysis
Condensation
Photosynthesis

Question 8

How does water as a solvent dissolve substances?

Answer 8

Anything polar or charged will dissolve in water as it will overcome the hydrogen bonding (between water molecules) and therefore the solute will be surrounded by the water molecules as they have hydrophobic and hydrophilic ends

Question 9

What are solutions needed for?

Answer 9

Chemical reactions

I.e the cytoplasm in cells is a solution

Question 10

How do water molecules ‘stick together’?

Answer 10

There are cohesive forces between water molecules meaning they ‘stick together’

Used in xylem vessels

Allows for surface tension

Question 11

How does water stick to other substances?

Answer 11

It has adhesive properties which is an attraction between molecules of different substances

Question 12

What is used in transpiration?

Answer 12

High capillary action

Question 13

What is high latent heat of vaporisation?

Answer 13

Latent - period where a state is changing (plateau on graph)

Therefore needs a lot of energy to change from liquid to gas because you have to over come the hydrogen bonds

Question 14

What is specific heat capacity?

Answer 14

The energy needed to raise the temperature of 1g of a substance by 1 degree

Question 15

What is water’s specific heat capacity?

Answer 15

4.184 joules

Question 16

Why is it important that water has a high specific heat capacity?

Answer 16

Important for internal environments: easier to maintain a stable body temperature which is essential for enzyme action (because it takes a lot of energy to gain or lose degrees)

Important for external environments: it resists temperature changes i.e sand is hot whilst the sea is cool even though it received the same amount of energy
Regulates temp of planet - sea temp not rising

Question 17

Why is water being polar significant?

Answer 17

The molecules attract to each other because of the polarity
Causing hydrogen bonds between the molecules
Therefore cohesion between molecules

Question 18

What is significant about the solid state of water? Why?

Answer 18

Ice is less dense than it’s liquid form of water

This is because of the hydrogen bonds

Question 19

What are ions?

Answer 19

Formed by loss or gain of electrons

Question 21

What is a cation?

Answer 21

A positive ion

Pawsitive

Question 22

What is an inorganic ion?

Answer 22

Doesn’t contain carbon (some exceptions)
Vital for cellular activity in animals and plants

Called electrolytes in body tissues

Question 23

Where do inorganic ions occur?

Answer 23

In solutions in the cytoplasm of cells

In bodily fluids of organisms

Question 24

What determines an ion’s specific role?

Answer 24

It’s properties

Question 25

What is an anion?

Answer 25

A negative ion

Question 27

What is the role of iron?

Answer 27

Used in the prosthetic group in haemoglobin (Haem group)

Responsible for the affinity of binding oxygen to haemoglobin

Question 28

What is the role of hydrogen?

Answer 28

Controlling the pH
More H+ ions = high acidity
It could denature enzymes and proteins that are working in your body

Needed for ATP synthesis

Question 29

What is the role of sodium?

Answer 29

Used for co-transport for absorbing simple sugars and amino acids

Conducting nerve impulses

Question 30

What is the role of phosphate?

Answer 30

Used in the sugar backbone of DNA and RNA

Used in ATP

Question 31

What is the role of magnesium?

Answer 31

Makes bones and teeth stronger

Used as a prothetic group in chlorophyll