TEST 2 - WATER

Question 1

Water Structure

Answer 1

• Two hydrogens covalently bonded to an oxygen.
• POLAR molecule
• When water molecules bond together – Hydrogen Bonding

Question 2

Significance of Water

Answer 2

• Coolant
• Transport Medium
• Habitat

Question 3

Adhesive / Cohesive - Water property

Answer 3

• Polarity / H-Bonds
• Cohesion - Water sticks to other water molecules (H-Bonds)
• Adhesion - Water sticks to other polar / charged molecules

Examples: Surface Tension
- Capillary Action - Adhesion
- Transpiration - Cohesion

Question 4

Transparency - Water property

Answer 4

• Depends on the amount of particles in the water
• 200m depth

Question 5

Buoyancy - Physical Property of Water

Answer 5

• Vertical upward force by a liquid or gas
• Depends on the object’s density
• Organisms that have a density close to water tend to float.
• Ice is < dense than water and floats at surface. Ice protect water from cold air.

Question 6

Viscosity - Physical Property of Water

Answer 6

• Resistance of a fluid to flow.
• Water has a very low viscosity (That is why it can flow easy)
• It is caused due to internal friction.

Question 7

Thermal Properties of Water

Answer 7

Hydrogen Bonding -
- water can absorb significant amounts of heat before changing state
- H-Bonds need to be broken/formed to change state
Application:
- Excellent medium for living organisms.
- Evaporative Cooling

Question 8

Specific Heat Capacity - Physical Property

Answer 8

Specific heat capacity is the amount of energy needed to change the temperature of 1g water by 1C is 4.18J.

Because of high specific heat capacity, the temperature of large bodies of water remain the same = good for organisms.

Question 9

Freezing

Answer 9

Form of H Bonds

Question 10

Solvent Properties

Answer 10

• Hydrogen Boning and Polarity
• Universal solvent: can dissolve any polar or ionic substance
• Polar attraction of large quantities of water weaken other intermolecular forces
• Diassociation
• Forms Hydration Shells
• Application - Transport

Question 11

Evaporation

Answer 11

Break of H Bonds

Question 12

Importance of Water as a Solvent

Answer 12

• Cytoplasm
• Fluid inside all organelles
• Between cells of multicellular organisms - interstitial fluid
• transport
• Part of the blood (Plasma)
• Stable medium for aquatic life
• Needed for many enzymatic reactions

Question 13

Surface Tension

Answer 13

Cohesion forces make water so tight together that it creates a surface tension. It allows it to resist external forces. - Example of Cohesive property

Question 14

Capillary action

Answer 14

The tendency of liquid to move up against gravity - Adhesive property

Question 15

Hydrophilic

Answer 15

Attracted to water

Question 16

Metabolism

Answer 16

The sum of the chemical reactions in the body that change food into energy - Example of solvent property