Special Properties of Water

1
Chapter 2

• Special Properties of Water

2
Water Facts

• 70 of our bodies are made up of water
• 75 of the earth is made up of water

3
Water Characteristics

• 2 hydrogen atoms and 1 oxygen atom (H20)
• Has a large negative end and a small positive end
  (causes water to act like a magnet)
• Water is covalently bonded (strong bond)

4
Unusual Properties of Water

• High specific heat
• High surface tension
• Good Solvent
• High heat of vaporization
• High heat of fusion
• Expansion on freezing

5
High Specific Heat

• Water heats more slowly and retains heat longer
  than most substances

6
High Surface Tension

• Water bonds to itself and other substances
• A. cohesion- attraction between substances of
  SAME
• kind (bugs walk on water)
• B. Adhesion- attraction between substance of
  DIFFERENT kind
• (water rises from roots up stem to leaves)
• 1. capillary action- ability of water to move
  up a narrow tube

http//www.youtube.com/watch?vCT4pURpXkbY
7
Good Solvent

• Many substances dissolve in water
• because it is a polar covalent molecule
• Solute- substance being dissolved
• (kool-aid powder)
• Solvent- substance doing the dissolving
• (water used to mix kool-aid)
• Solution mixture of 1 or more substances evenly
  distributed in another substance Solvent
  Solute (Kool-Aid)
• Concentration- amount of solvent compare the
  amount of solute (the more solute, the greater
  the concentration)

8
Remember

• Polar Molecules dissolve in water ( NaCl)
• http//www.mhhe.com/physsci/chemistry/animations/c
  hang_7e_esp/clm2s3_4.swf
• Nonpolar Molecules do not dissolve in water
  (oil)
• http//www.youtube.com/watch?vAeZU1yJlZO0

9
High Heat of Vaporization

• Takes a lot of heat to evaporate liquid water

10
High Heat of Fusion

• Takes a lot of heat to convert water to gas

11
Expansion on freezing

• Liquid water is the only common substances that
  expands rather then contracts when it freezes

12
Water Properties Review

• High specific heat
• High surface tension
• Capillary Action
• Good Solvent
• High heat of vaporization
• High heat of fusion
• Expansion on freezing

13
Water Chemistry

• Water bonds are strong (covalent) but can break
• the amount of H and OH- ions determines the
  pH of a substance
• pH is important because organisms function at a
  balanced pH
• pH stands for power of hydronium ion
• pH value used to express the acidity (acidic)
  or alkalinity (basic) of a solution

H20 ? H OH-
Water is so much phun dude!!
Lets get phunky!!
Learning can be phun!
14
pH Scale
based on the factor of 10 Ex. pH of 4 is 10
times stronger than a pH of 5 pH of 12 is
100 times stronger than pH of 10
15
pH continued

• pH scale- measure of the strengths of acids and
  bases that range from 0 to 14
• ACIDIC- pH lt 7 (form hydrogen (H) ions in a
  solution.)
• ex. lemon juice, vinegar, stomach acid
• NEUTRAL ph 7 ex. water, milk, blood
• BASIC pH gt 7 (forms hydroxide (OH- ) ions in a
  solution)
• ex. bleach, dishwashing detergents

16
Neutralization

• Neutralization occurs when strong bases mix with
  strong acids

17
Chapter 2 Foldable

• 1. Atom 8.Adhesion
• 2. Element 9.Solution
• 3. Compound 10.Solvent
• 4. Molecule 11.Solvent
• 5. Ion 12. Solute
• 6. Isotope 13. Acid
• 7. Cohesion 14.Base