Lecture 14 - Water P1

Question 1

what percentage of the earths surface is currently covered in water

Answer 1

71%

Question 2

what percentage of earths water do oceans hold

Answer 2

96.5%

Question 3

where does the rest of water exist

Answer 3

• Freshwater in rivers and lakes
• Frozen water in glaciers and ice caps
• Soil moisture and GROUNDWATER AQUIFERS
• WATER VAPOR in ATMOSPHERE

Question 4

what are the phases or physical states of water

Answer 4

solid (ice, snow)
liquid (rain, surface water, groundwater)
gas (water vapour, humidity)
aqueous (dissolved in water)

Question 5

surface water

Answer 5

water located on top of land and surrounded by land (e.g., stream, rivers, lakes, wetlands)

Question 6

groundwater

Answer 6

water present beneath Earth’s surface
in rock and soil pore spaces and in the fractures of rock formations.

Question 7

water from a SEA or OCEAN.

Answer 7

seawater

Question 8

MOLECULE + what is what

Answer 8

two or more ATOMS connected/
bonded together.
Water, H2O, is a MOLECULE as it consists of 3
atoms bound together.

Question 9

Water is main component of most ___

Answer 9

cells

Question 10

percentage of water in humans

Answer 10

✓ Newborn babies: 78% water
✓ 1 year old infant: 65% water
✓ Adults: 55 – 60% water (fat holds less
water than muscle, so amounts vary).
✓ % water drops with age.

HE SAID HE WONT ASK THIS BECAUSE EVERY SITE HAS DIFF NUMBERS JUST HAVE TO MOSTLY KNOW THAT IT DROPS WITH AGE!!

Question 11

water in different organs

Answer 11

✓ lungs: 83% water
✓ kidneys: 79% water
✓ brain: 73% water
✓ heart: 73% water

Question 12

freshwater

Answer 12

water containing less than
1,000 milligrams per liter of dissolved solids,
most often salt.

Question 13

less than ___ of earths water is freshwater

Answer 13

3%
> 68% found in glaciers/ice caps
> 30% found in GROUNDWATER
0.3% found in SURFACE WATER

Question 14

most accessible drinking water comes from
___% of ___% of Earth’s water!

Answer 14

0.3% of 3%

Question 15

More than __% of Earth’s water is not usable
for drinking unless we use VARIOUS
technologies (desalination, dig wells, etc…).

Answer 15

99%

Question 16

About __% of world’s fresh SURFACE WATER
in Canada.

Answer 16

20%

Question 17

Canada’s lakes and rivers cover __% of surface
area.

Answer 17

12%

Question 18

Canada has more ___ than any other country in world.

Answer 18

“lake area” (area covered by
lakes)

Question 19

Great Lakes (Canada/USA) contain ___% of
global fresh SURFACE WATER.

Answer 19

18%

Question 20

25% of Canadians depend on ___
for drinking water

Answer 20

GROUNDWATER

Question 21

how does water bond

Answer 21

Atoms within a single water molecule bond together by sharing electrons
They form 2 OXYGEN (O) – HYDROGEN (H)
COVALENT BONDS.

Question 22

what are covalent bonds

Answer 22

bonds formed when share 2
electrons.

Question 23

INTRAMOLECULAR BONDING

Answer 23

bonding between atoms occurring within a molecule (i.e., “intra” = within molecule)

Question 24

Between water molecules, we encounter weaker but extremely important interactions known as ____

Answer 24

INTERMOLECULAR FORCES (i.e., “inter” = between molecules)

Question 25

what are intermolecular forces

Answer 25

- relatively weak interactions that occur between molecules - keep water molecules together to a certain extent

Question 26

what happens when change state (e.g., solid to liquid, etc), in water

Answer 26

individual molecules remain intact/remain H2O. Molecules do NOT come apart - What changes when change PHYSICAL STATE is INTERMOLECULAR FORCES between molecules. Nothing changing within molecules.

Question 27

water is a ____ molecule

Answer 27

polar

Question 28

oxygen likes to ___ electrons

Answer 28

HOG - Even though it’s supposed to share electrons with hydrogen (in forming COVALENT BONDS), it pulls “shared” electrons closer to itself - As a result, oxygen in water is ELECTRON-RICH, while two hydrogens are ELECTRON-POOR In same way as Earth has 2 POLES (a North Pole and a South Pole), water also has 2 POLES (an ELECTRON-RICH pole and an ELECTRON-POOR pole. Therefore, water is POLAR

Question 29

Oxygen in water is ____ as it holds electrons closer to itself

Answer 29

“PARTIALLY NEGATIVE " δ-

Question 30

review great lakes on map!!

Answer 30

he might ask (he said) WAIT HE JUST SAID ONLY IF HE INCLUDES THEM IN THE NOTES

Question 31

Hydrogens in water are ___ as the oxygen is pulling their electrons away.

Answer 31

“PARTIALLY POSITIVE” δ+

Question 32

In science, “partially” is represented by ____

Answer 32

the Greek letter delta δ

Question 33

dipole

Answer 33

2-poles - water has 2 poles (one PARTIALLY POSITIVE, one PARTIALLY NEGATIVE).

Question 34

Water molecules are attracted to one another through ___

Answer 34

DIPOLE-DIPOLE ATTRACTION

Question 35

what are DIPOLE-DIPOLE ATTRACTION

Answer 35

attractive force experienced when POLAR molecules line up so that PARTIALLY POSITIVE end of one molecule lines up with/is close to PARTIALLY NEGATIVE end of another molecule. - In DIPOLE-DIPOLE ATTRACTION, molecules maximize attractive POSITIVE-NEGATIVE interactions and minimize repulsive POSITIVEPOSITIVE and NEGATIVE-NEGATIVE interactions.

Question 36

Water molecules undergo a specific DIPOLE-DIPOLE INTERACTION called ___

Answer 36

hydrogen bonding

Question 37

what is hydrogen bonding

Answer 37

Whenever hydrogen is bound to very ELECTRONEGATIVE oxygen, nitrogen or fluorine atoms within a molecule, we encounter very strong HYDROGEN-BONDING interactions between individual molecules. unusually strong DIPOLE-DIPOLE attractions occurring among molecules containing hydrogen bonded to highly electronegative oxygen, nitrogen or fluorine atoms. HYDROGEN BONDING has an enormous impact on the way water behaves!

Question 38

ELECTRONEGATIVE ATOMS

Answer 38

Atoms that like to pull electrons towards themselves.

Question 39

what are the most ELECTRONEGATIVE ATOMS:

Answer 39

Oxygen, Nitrogen, Fluorine

Question 40

In water, hydrogen is bound to ___ Therefore, we have ___

Answer 40

1. ELECTRONEGATIVE oxygen. 2. HYDROGEN BONDING.

Question 41

what is gas to liquid

Answer 41

condensation

Question 42

what is liquid to gas

Answer 42

evaporation

Question 43

what is liquid to solid

Answer 43

freezing

Question 44

what is solid to liquid

Answer 44

melting

Question 45

what is solid to gas

Answer 45

sublimation

Question 46

what is gas to solid

Answer 46

deposition