Water and inorganic ions

Question 1

structure of Water

Answer 1

consists of one atom of oxygen chemically bonded to 2 atoms of hydrogen

Question 2

What type of molecule is water

Answer 2

polar molecule

Question 3

why is water dipolar

Answer 3

the oxygen atom has a slight negative charge and the hydrogen atoms have a slight positive charge

Question 4

How do water molecules stick together

Answer 4

different poles attract and therefore the positive pole of one water molecule will be attracted to the negative pole of another water molecule. The attractive force between these opposite forces is a hydrogen bond

Question 5

specific heat capacity of water

Answer 5

because water molecules stick together they require more energy to seperate them. For this reason the boiling point of water is higher than expected. Water therefore acts as a buffer against a sudden temperature variation

Question 6

latent heat of vaporisation of water

Answer 6

hydrogen bonding between water molecules means that it requires a lot of energy to evaporate 1g of water

Question 7

cohesion and surface tension in water

Answer 7

the tendency for molecules to stick together is known as cohesion. with its hydrogen bonding water has large cohesive forces and these allow it to be pulled up through a tube such as the xylem vessel.
In the same way where water molecules meet air they tend to be pulled back into the body of water rather than escaping from it (surface tension)

Question 8

Importance of water to living organisms

Answer 8

water is the main constituent of all living organisms.
-mammals are typically 65% water

Question 9

water in metabolism

Answer 9

water is used to break down many complex molecules by hydrolysis

Question 10

water as a solvent

Answer 10

water readily dissolves other substances
-gases
-wastes
-inorganic ions
enzymes

Question 11

features of water

Answer 11

-its evaporation cools organisms and allows them to control their temperature
-it’s not easily compressed and therefore provides support
-it’s transparent and therefore aquatic plants can photosynthesis

Question 12

properties of water

Answer 12

• very high specific heat capacity
• very high latent heat of vaporisation
• water as a solvent
• cohesion
• metabolic reactions

Question 13

inorganic ions

Answer 13

is a charged atom that does not contain carbon

Question 14

where are inorganic ions found

Answer 14

in organisms where they occur in solution in the cytoplasm of cells and in body fluids as well as part of larger molecules

Question 15

examples of inorganic ions and their functions

Answer 15

iron ions- transport of oxygen
phosphate ions-structural role in DNA
and storing energy in ATP#
hydrogen ions- determining the pH of solutions and therefore functioning of enzymes
sodium ions- transport of glucose and amino acids across plasma membranes

Question 16

State and explain the property of water that helps to prevent temperature increase in a cell.

Answer 16

-High specific heat capacity
-Buffer changes in temperature