Water

Question 1

Structure of Water

Answer 1

• 1 Oxygen covalently bonded to 2 Hydrogens
• Oxygen has a higher affinity for electrons therefore leaving a delta negative charge in the Oxygen and a delta positive charge on the Hydrogens
• water molecule can form up to 4 hydrogen bonds

Question 2

Property and function of water (1)

Answer 2

• Property: Water is a good solvent of polar and ionic substances
• Function: it’s essential for transport of nutrients and waste products in the body (water in the blood)

Question 3

Property and function of water (2)

Answer 3

-Property: Water has a high specific heat capacity, it takes a lot of energy to heat it up and it stores energy so it takes long to cool down (due to LOTS of weak hydrogen bonds
Function: regulates temperature of oceans, organisms prevents rapid temperature change

Question 4

Property and function of water (3)

Answer 4

Property: high latent heat of vaporisation as water heats from 100C liquid to 100C gas, thermal energy is converted into breaking all the hydrogen bonds
Function: evaporation from the surface of organisms removes heat eg sweating from the skin of a mammal or transpiration from the stomata of a leaf

Question 5

Property and function of water (4)

Answer 5

• Property: anomalous expansion, as water freezes the water molecules form exactly 4 hydrogen bonds with the surrounding water molecules, distance between molecules is increased solid water is LESS DENSE than liquid water
• Function: ice forms on the surface of water insulates water beneath and prevents heat loss

Question 6

Property and functions of water (5)

Answer 6

• Property: high cohesion of water molecules, water molecules stick together by hydrogen bonds
• Function: water can move by mass flow eg water being drawn up via the xylem vessel