Mrs. MacWilliamsMrs. MacWilliams

Academic BiologyAcademic Biology

I.I. Properties of WaterProperties of Water1. Liquid at most of Earth1. Liquid at most of Earth’’s s temperaturestemperatures2. EXPANDS WHEN IT FREEZES!2. EXPANDS WHEN IT FREEZES!-unlike most things that expand when -unlike most things that expand when they get hotthey get hot3. WORLDS GREATEST SOLVENT3. WORLDS GREATEST SOLVENT4. MOST ABUNDANT COMPOUND4. MOST ABUNDANT COMPOUND5. only natural substance that is found 5. only natural substance that is found in all three states -- liquid, solid (ice), in all three states -- liquid, solid (ice), and gas (steam) -- at the temperatures and gas (steam) -- at the temperatures normally found on Earth.normally found on Earth.

BIll Nye Solid Liquid GasBIll Nye Solid Liquid Gas

Properties of water Properties of water continuedcontinued

6. Freezing point: 6. Freezing point: 0 0ooCC/32/32ooF F 7. Boiling point: 7. Boiling point: 100100o o CC/212/212oo F F8. Water has a high 8. Water has a high specific heat specific heat index. This means that water can index. This means that water can absorb a lot of heat before it absorb a lot of heat before it begins to get hot.begins to get hot.

9. Due to the uneven distribution 9. Due to the uneven distribution of of electrons between oxygen and electrons between oxygen and hydrogen atoms…. Water is POLAR. hydrogen atoms…. Water is POLAR. This polarity allows for cohesion (to This polarity allows for cohesion (to itself) and adhesion (to other itself) and adhesion (to other things) to occur.things) to occur.**Water is neutral overall, however, **Water is neutral overall, however, the hydrogens have a slightly the hydrogens have a slightly positive charge and oxygen has a positive charge and oxygen has a slightly negative charge.slightly negative charge.

II. BondingII. Bonding1. 1. Hydrogen bonding Hydrogen bonding - type of bond - type of bond between an electronegative atom and a between an electronegative atom and a hydrogen atom bonded to another hydrogen atom bonded to another electronegative atom. electronegative atom. *Only Oxygen, Fluorine, and Nitrogen *Only Oxygen, Fluorine, and Nitrogen can form hydrogen bonds can form hydrogen bonds

a. a. AdhesionAdhesion - Attraction between - Attraction between molecules of molecules of differentdifferent substances. substances.

Example: Water & glassExample: Water & glass

b. b. CohesionCohesion - Attraction between - Attraction between molecules of the molecules of the SAMESAME substance. substance.

Example: Water drops on pennyExample: Water drops on penny Hydrogen bonding

c. c. Hydrophilic Hydrophilic – Molecules that – Molecules that form hydrogen bonds with waterform hydrogen bonds with water

example: vinegar and water example: vinegar and water (mix together (mix together and don’t and don’t

separate)separate)

d. d. HydrophobicHydrophobic - Molecules that - Molecules that can't form hydrogen bonds can't form hydrogen bonds

example: oil and water (do example: oil and water (do not stay mixed together)not stay mixed together)

Water bonding cont.Water bonding cont.

22. . Surface tensionSurface tension – measure of – measure of how how difficult it is to break the difficult it is to break the surface of the watersurface of the water

RAFT SPIDERRAFT SPIDER

Cohesion is stronger at the surface of the water

Water bonding cont.Water bonding cont.

33. . CapillarityCapillarity – the ability of – the ability of water to move water to move up through narrow up through narrow channelschannels

*Water has a very high surface *Water has a very high surface tension. Surface tension is tension. Surface tension is responsible for capillary action.responsible for capillary action.

Water bonding cont.Water bonding cont.

4. Each water molecule can 4. Each water molecule can hydrogen bond to 4 other water hydrogen bond to 4 other water molecules.molecules.

*See next slide to learn*See next slide to learn

how to draw this diagramhow to draw this diagram

You will You will be asked be asked to draw to draw

this this diagram diagram on a on a quiz quiz or test.or test.

solid lines are covalent bonds dotted lines are

hydrogen bonds

III. Mixtures and SolutionsIII. Mixtures and Solutions1. 1. MixtureMixture -Two or more compounds mix -Two or more compounds mix together, but together, but do NOT chemically do NOT chemically combinecombine..2. 2. Solution-Solution- one substance DISSOLVED one substance DISSOLVED in anotherin another

SolSolvvent- dissolent- dissolvves a substancees a substanceSolute- the substance Solute- the substance

3. 3. SuspensionSuspension - A mixture where - A mixture where materials materials dodo not dissolvenot dissolve, but , but separate separate and settle outand settle out

Example: Example: Garlic, onions, and bell peppers Garlic, onions, and bell peppers in Italian dressing (vinegar and water in Italian dressing (vinegar and water layer)layer)

VIDEOSVIDEOS

Properties of WaterProperties of Water PAINFUL example of water PAINFUL example of water

SURFACE TENSIONSURFACE TENSION