water 1 Flashcards
what is the percentage of earth’s surface that is currently covered in water?
71%
what’s the percentage that the ocean holds of earth’s water?
96.5%
other than the ocean, what does the rest of water exists as?
✓ Freshwater in rivers and lakes
✓ Frozen water in glaciers and ice caps
✓ Soil moisture and GROUNDWATER AQUIFERS
✓ WATER VAPOR in ATMOSPHERE
why is water so special?
Water is special. Water only molecule on earth occurring naturally as solid, liquid & gas (i.e., in three PHASES or PHYSICAL STATES).
Currently, around this very college, water exists as a SOLID (ice, snow), LIQUID (rain, SURFACE WATER, GROUNDWATER) and GAS (water vapour, humidity).
what is surface water?
water located on top of land and surrounded by land (e.g., stream, rivers, lakes, wetlands)
what is groundwater?
water present beneath Earth’s surface in rock and soil pore spaces and in the fractures of rock formations
what is seawater?
water from a SEA or OCEAN
what is the percentage of our body made of water and then the different organs?
High percentages of our bodies are made up of water:
✓ 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.
Consider different organs:
✓ lungs: 83% water
✓ kidneys: 79% water
✓ brain: 73% water
✓ heart: 73% water
what is freshwater?
water containing less than 1,000 milligrams per liter of dissolved solids, most often salt
what is the percentage of freshwater on earth and the proportions from that?
less than 3%:
> 68% found in glaciers/ice caps
> 30% found in GROUNDWATER
0.3% found in SURFACE WATER! (where most accessible drinking water comes from)
how do we get to use more than 99% of earth’s water?
VARIOUS technologies (desalination, dig wells, etc…)
what’s the percentage of the world’s fresh surface water in Canada?
20%
what is the percentage Canada’s lakes and rivers cover of surface area and what is its ranking in the world?
12%
Canada has more “lake area” (area covered by
lakes) than any other country in world
what is the percentage of global fresh surface water the Great Lakes (Canada/USA) contain6
18%
what is intramolecular bonding?
bonding between atoms occurring within a molecule (i.e., “intra” = within molecule)
what is the percentage of Canadians that depend on groundwater for drinking water?
25%
what are intermolecular forces?
relatively weak interactions that occur between molecules.
INTERMOLECULAR FORCES keep water molecules together to a certain extent.
what changes when physical state changes?
INTERMOLECULAR FORCES between molecules.
Nothing changing within molecules
explain the water polar molecule.
Remember that ELECTRONS have a negative charge.
Oxygen likes to “HOG” electrons.
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.
Oxygen in water is “PARTIALLY NEGATIVE” as it
holds electrons closer to itself.
Hydrogens in water are “PARTIALLY POSITIVE” as
the oxygen is pulling their electrons away.
In science, “partially” is represented by the Greek
letter delta, δ.
We say oxygen is “PARTIALLY NEGATIVE” or δ-.
We say hydrogen is “PARTIALLY POSITIVE” or δ+.
what is a dipole?
2 poles
what is 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
what is hydrogen bonding?
unusually strong DIPOLE-DIPOLE attractions occurring among molecules containing hydrogen
bonded to highly electronegative oxygen, nitrogen or fluorine atoms.
what is electronegative atoms?
Atoms that like to pull electrons towards themselves
what are the most electronegative atoms?
Oxygen, Nitrogen, Fluorine
