Water

Question 1

Four Unique Properties of Water

Answer 1

1) Cohesion
2) Ability to moderate temperatures
3) Expansion upon freezing
4) Versatility as a solvent

Question 2

Property #1: Cohesion

Answer 2

Hydrogen bonding between water molecules.

Results in:
- High surface tension
- Adhesion
- Transpiration (movement against gravity in plants)

Question 3

Property #2: Ability to moderate temperature

Answer 3

Water can absorb or release a large amount of heat with only a slight change in its own temperature due to its high specific heat

Water can also cool down areas through evaporation

Ice can insulate bodies of water

Question 4

Property #3: Expansion upon freezing

Answer 4

While other materials contract when they solidify, water expands.

less dense as a solid than as a
liquid

Ice can insulate bodies of water, preventing everything from freezing to death

Question 5

Property #4: Versatility as a solvent

Answer 5

Water can dissolve ionic compounds, many nonionic compounds, as well as molecules such as proteins as long as they have polar and ionic regions on their surface.

Question 6

Surface tension (cohesion)

Answer 6

force necessary to stretch or break the surface of a liquid

Water has greater surface tension than most liquids because hydrogen bonds resist stretching or breaking the surface.

Question 7

Adhesion (cohesion)

Answer 7

the clinging of one substance to another (water “sticks” to some surfaces like plant leaves), fighting gravity

Question 8

Transpiration (cohesion)

Answer 8

Water moves “up” plants against gravity’s pull

Question 9

Heat

Answer 9

total amount of kinetic energy (KE) due to molecules moving in matter.

Question 10

Temperature

Answer 10

intensity of heat in a body of matter due to the average kinetic energy of molecules.

The quicker the movement, the higher the temp

Question 11

Calorie

Answer 11

the amount of heat required to raise the temperature of 1 g of water by 1ºC

also the amount of heat released when 1 g of water cools by 1ºC

Question 12

Specific Heat

Answer 12

the amount of heat that must be absorbed/ lost for 1 g of water to change its temperature by 1ºC

The specific heat of water is 1 cal * ºC

Water resists changing its temperature because of its high specific heat

Question 13

Evaporative Cooling

Answer 13

Evaporation= liquid to gas

Heat of vaporization= heat needed for 1 g of liquid to be converted to gas

evaporative cooling: the cooling of a surface as liquid turns to gas

Question 14

Solution

Answer 14

a liquid that is a completely homogeneous mixture of substances

Question 15

Solvent

Answer 15

dissolving agent of a solution (usually the liquid)

Question 16

Solute

Answer 16

what is being dissolved

Question 17

Hydrophilic Substances

Answer 17

attracted to water

Question 18

Hydrophobic substances

Answer 18

repelled by water

Question 19

Why are the properties of water important to life?

Answer 19

Cohesion- helps transport of water and nutrients against gravity in plants. Also bugs can move in water and not drown bc of surface tension.

Ability to moderate temperature- keeps temperatures within ranges that permit life to exist

Expansion upon freezing - helps ice float. If ice sank, it would freeze everything below

Solvency - Most chemical reactions in organisms involve solutes dissolved in water

Question 20

Acid

Answer 20

a substance that increases the H+ concentration of a solution

Question 21

Base

Answer 21

a substance that reduces the H+ concentration of a solution

Question 22

Buffers

Answer 22

minimize changes in concentration of H+ and OH- in a solution (weak acids and bases)

Helps us maintain a pH that does not change extremely (close to 7)

Buffers keep blood at pH ~7.4

If blood drops to 7 or up to 7.8, then death

Question 23

H2CO3 (carbonic acid) + HCO3- (bicarbonate) + H+

Answer 23

important
buffers in blood plasma

Question 24

When CO2 mixes with ocean water, what happens?

Answer 24

Ocean acidification. Threatens corals, reefs, and marine biosystems