Lecture 14 - Water P1 Flashcards
what percentage of the earths surface is currently covered in water
71%
what percentage of earths water do oceans hold
96.5%
where does the rest of water exist
- Freshwater in rivers and lakes
- Frozen water in glaciers and ice caps
- Soil moisture and GROUNDWATER AQUIFERS
- WATER VAPOR in ATMOSPHERE
what are the phases or physical states of water
solid (ice, snow)
liquid (rain, surface water, groundwater)
gas (water vapour, humidity)
aqueous (dissolved in water)
surface water
water located on top of land and surrounded by land (e.g., stream, rivers, lakes, wetlands)
groundwater
water present beneath Earth’s surface
in rock and soil pore spaces and in the fractures of rock formations.
water from a SEA or OCEAN.
seawater
MOLECULE + what is what
two or more ATOMS connected/
bonded together.
Water, H2O, is a MOLECULE as it consists of 3
atoms bound together.
Water is main component of most ___
cells
percentage of water in humans
✓ 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!!
water in different organs
✓ lungs: 83% water
✓ kidneys: 79% water
✓ brain: 73% water
✓ heart: 73% water
freshwater
water containing less than
1,000 milligrams per liter of dissolved solids,
most often salt.
less than ___ of earths water is freshwater
3%
> 68% found in glaciers/ice caps
> 30% found in GROUNDWATER
0.3% found in SURFACE WATER
most accessible drinking water comes from
___% of ___% of Earth’s water!
0.3% of 3%
More than __% of Earth’s water is not usable
for drinking unless we use VARIOUS
technologies (desalination, dig wells, etc…).
99%
About __% of world’s fresh SURFACE WATER
in Canada.
20%
Canada’s lakes and rivers cover __% of surface
area.
12%
Canada has more ___ than any other country in world.
“lake area” (area covered by
lakes)
Great Lakes (Canada/USA) contain ___% of
global fresh SURFACE WATER.
18%
25% of Canadians depend on ___
for drinking water
GROUNDWATER
how does water bond
Atoms within a single water molecule bond together by sharing electrons
They form 2 OXYGEN (O) – HYDROGEN (H)
COVALENT BONDS.
what are covalent bonds
bonds formed when share 2
electrons.
INTRAMOLECULAR BONDING
bonding between atoms occurring within a molecule (i.e., “intra” = within molecule)
Between water molecules, we encounter weaker but extremely important interactions known as ____
INTERMOLECULAR FORCES (i.e., “inter” = between molecules)
what are intermolecular forces
- relatively weak interactions that occur between molecules
- keep water molecules
together to a certain extent
what happens when change state (e.g., solid to liquid, etc), in water
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.
water is a ____ molecule
polar
oxygen likes to ___ electrons
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
Oxygen in water is ____ as it
holds electrons closer to itself
“PARTIALLY NEGATIVE “ δ-
review great lakes on map!!
he might ask (he said) WAIT HE JUST SAID ONLY IF HE INCLUDES THEM IN THE NOTES
Hydrogens in water are ___ as the oxygen is pulling their electrons away.
“PARTIALLY POSITIVE” δ+
In science, “partially” is represented by ____
the Greek letter delta δ
dipole
2-poles
- water has 2 poles (one PARTIALLY POSITIVE, one PARTIALLY NEGATIVE).
Water molecules are attracted to one another through ___
DIPOLE-DIPOLE ATTRACTION
what are DIPOLE-DIPOLE ATTRACTION
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.
Water molecules undergo a specific DIPOLE-DIPOLE INTERACTION called ___
hydrogen bonding
what is hydrogen bonding
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!
ELECTRONEGATIVE ATOMS
Atoms that like to pull electrons towards themselves.
what are the most ELECTRONEGATIVE ATOMS:
Oxygen, Nitrogen, Fluorine
In water, hydrogen is bound to ___ Therefore, we have ___
- ELECTRONEGATIVE
oxygen. - HYDROGEN BONDING.
what is gas to liquid
condensation
what is liquid to gas
evaporation
what is liquid to solid
freezing
what is solid to liquid
melting
what is solid to gas
sublimation
what is gas to solid
deposition
