Chapter 3 Water

Question 1

What % of the Earth is covered in water?

Answer 1

75%

Question 2

What % of the human body is water?

Answer 2

70-90%

Question 3

What are the 4 emergent properties of water?

Answer 3

1. Cohesive Behavior
2. Ability to Moderate Temp.
3. Expansion upon Freezing
4. Universal Solvent

Question 4

What makes water cohesive ?

Answer 4

H-Bonds

Question 5

Cohesive

Answer 5

The attraction of molecules for other molecules of the same kind

Question 6

Adhesion

Answer 6

the tendency of water molecules to attracted, or “stick”, to other substances

Question 7

Surface Tension

Answer 7

how difficult it is to break the surface of a liquid

Question 8

What is surface tension affected by?

Answer 8

Temp.

Question 9

What is heat?

Answer 9

the energy associated w/movement of atoms &, molecules in matter

Question 10

Temperature

Answer 10

measures the intensity of heat

Question 11

What causes H-bonds to break?

Answer 11

Heat is being absorbed

Question 12

What happens when H-bonds form?

Answer 12

Heat is released

Question 13

Specific Heat

Answer 13

the amount of heat that must be absorbed or lost to change the temp of 1 g of a substance by 1 degree C.
Water: 1 C/g
Ethyl: 6 C/g
Acetone: .51 C/g

Question 14

What does Specific Heat allow large bodies of water to do?

Answer 14

It allows large bodies of water to absorb & store large amounts of heat while changing the temp. slightly. Allowing ocean’s temps to fluctuate less than land.

Question 15

Heat of Vaporation

Answer 15

The energy/heat required to change 1g of water from liquid to gas

Question 16

Evaporative Cooling

Answer 16

When people sweat, water molecules are released from the body (the one w/ the highest energy leave) The molecules that are left behind have less energy & therefore cool down.

As sweat evaporates it absorbs heat to cool your body

Question 17

What is less dense liquid water vs ice

Answer 17

Ice

Question 18

Why is water less dense as a solid?

Answer 18

H-Bonding, the orientation of the bonds causes molecules to push farther apart which lowers density

Question 19

What temp. is water densest?

Answer 19

4 degree C

Question 20

What happens to the density of water lower than 4-degree C

Answer 20

The density decreases.

Question 21

B/c of Water’s expansion it prevents deep bodies of water from doing what?

Answer 21

Freezing bottom up

Question 22

As water freezes, what happens to the water below?

Answer 22

It gets insulated b/c of the release of heat

Question 23

What factors the seasonal transition of water less abrupt?

Answer 23

H bonds breaking absorbing heat & H-bonds forming releasing heat.

Question 24

Solution

Answer 24

liquid consisting of a uniform mixture of 2 or more substances

Question 25

Solvent

Answer 25

dissolving agent

Question 26

Solute

Answer 26

substance that dissolves

Question 27

Hydrophilic

Answer 27

Affinity to H20 Polar Ion Sugar & Salt Blood

Question 28

Hydrophilic

Answer 28

Affinity to H20 Polar Ion Sugar & Salt Blood

Question 29

Hydrophobic

Answer 29

Repel H2O Nonpolar Oil & Lipids Cell Membrane

Question 30

What do water molecules dissociate into?

Answer 30

H+ and OH-

Question 31

What do water molecules dissociate into?

Answer 31

H+ and OH-

Question 32

H+ + H2O = H3O+

Answer 32

Hydronium ion

Question 33

H20 - H+ =OH-

Answer 33

Hydroxide ion

Question 34

Acid

Answer 34

Increase in H+ concentration less than pH of 7 More H+ than OH-

Question 35

Bases

Answer 35

Decrease of H+ in a solution More OH- than H+ greater than 7

Question 36

Buffer System

Answer 36

Consists of a weak acid & its conjugated weak base Accept H+ ions when they are in excess & donate them when they are depleted Dissociate to replenish H+ Reassociate when H+ is too high

Question 37

Which property explains the ability of a water strider to walk on water?

Answer 37

Surface Tension

Question 38

3 effects of heat of vaporization

Answer 38

Moderates Earth's climate Accounts for severity of steam burns Releases heat and forms rain

Question 39

Ice floats, why is this property so important ?

Answer 39

If ice sank , eventually all ponds would freeze over, kill life

Question 40

Why is water such a fine solvent

Answer 40

Polarity & Hydrogen Bonds, molecules as large as proteins can dissolve in water as wall as bio fluid, sap & liquid in cells

Question 41

Olive oil doesn't dissolve in water, explain in terms of hydrogen bonding?

Answer 41

Oils are nonpolar molecules, hydrophobic molecules related to oils are a big part of cell membranes & are hydrophobic so the membrane doesn't dissolve. So for oil to dissolve in water they would have to break some of water's hydrogen bonds. Oil is nonpolar because of this in order for oil to dissolve it would have to break water’s hydrogen bonds. Which water will not do so they are separate.

Question 42

Calorie

Answer 42

the energy needed to raise the temp. of 1 g of water through 1 degree C.

Question 43

How does water high specific heat contribute to moderation of temp. How is this an important property for life?

Answer 43

Water's high specific heat makes it so that it takes a long to heat up & longer to cool down than the air & land. Which is important to the life that live in large bodies of water who needed a consistent temp. to live.

Question 44

Evaporation

Answer 44

liquid water changes to gaseous water