Chapter 3- Water And The Fitness Of The Enviroment

Question 1

Why is liquid water cohesive/adhesive? Relate it to living organisms.

Answer 1

Water sticks to water/ other molecules.
-The polarity of water results in hydrogen bonding
Ex)Water transport in trees using cohesion/adhesion
>Water has a high surface tension
-The surface of water is difficult to stretch/break
Ex)Certain organisms can walk across water

Question 2

Explain water has a high specific heat.

Answer 2

The amount of heat needed to raise 1g of the substance 1 degree Celsius
-Because of h-bonds it takes a big heat gain or loss for each degree of temperature change
-H-bonds must absorb heat to break and release heat to form
Ex)Water stabilizes temperature- climate moderation

Question 3

Define heat and temperature.

Answer 3

Heat is the total quantity of kinetic energy due to molecular motion.
Temperature is the average speed of molecules.

Question 4

Explain water has a high heat of vaporization.

Answer 4

The quantity of heat a liquid must absorb for 1g of it to covert to a gaseous state.
-For water molecules to evaporate, h-bonds must be broken, which requires heat
Ex)Evaporative cooling

Question 5

Explain water expands as it freezes.

Answer 5

The distance between water molecules increases from the liquid to the solid form.
-H-bonding causes water to be less dense as a solid than as a liquid
Ex)Ice doesn’t crush aquatic life and it releases heat to water below and insulates it

Question 6

Explain water is a versatile solvent.

Answer 6

Water will form a solution with many materials

Question 7

Hydrophilic and hydrophobic materials.

Answer 7

Hydrophilic materials (polar covalent) dissolve in water, while hydrophobic materials (nonpolar covalent) repel it.

Question 8

Acids

Answer 8

Materials that release hydrogen

-(ph

Question 9

Bases

Answer 9

Materials that can absorb hydrogen

-Often reduce hydrogen when producing OH

Question 10

Know the equation for ph.

Answer 10

-log[H]
-log[10^-6M]
6 is the pH level

Question 11

Explain buffers and their biological importance.

Answer 11

Materials that have both acid and base properties

• Resist pH shifts
• Works by accepting hydrogen ions when they’re in excess and donating hydrogen ions when they’ve been depleted
• Minimizing wide fluctuations in pH helps organisms maintain the pH of body fluids within the narrow range

Question 12

What are the five types of water properties?

Answer 12

1) Liquid water is cohesive/adhesive
2) Water has a high specific heat
3) High heat of vaporization
4) Expands as a solid
5) Versatile Solevent