1. Water H H O

2. Water Basics + +
Polar: part of a molecule is slightly positive, while another part is slightly negative
Oxygen “hogs” electrons from hydrogen
8 protons: 10 electrons
Negative charge
Hydrogen
1 proton: 0 electrons
Positive charge
Creates hydrogen bonds where one water sticks to another 1 1 1 1 1 2 6 1 5 2 3 4 -

3. Red = Oxygen (negative) White = Hydrogen (positive)- - - - - - - - - + + + + + + + + + + + + + + + + + + - - - - - - - - + + + + + + + + + + + + + + + + + + - - - - - - - - - + + + + + + + + + + + + + + + + + +

4. Water Properties High specific heat: Resists temp changes
Much energy needed to break water bonds
Helps to maintain a constant body temp
Cohesion: polar water molecules attracted to other polar water molecules
Adhesion: polar water sticks to other molecules
7ml
6.8ml
Why can this insect walk on water?
It is not heavy enough to break the bonds that hold the water molecules together.

5. Solutions Solution: mixture where 1 substance dissolves in another
2 parts to a solution
1) Solute: substance that dissolves
Atoms, ions, molecules
2) Solvent: substance in which the solute is dissolved
Usually water
Solution S U G A R K O O L A I D

6. Solutions Solution: mixture where 1 substance dissolves in another
2 parts to a solution
1) Solute: substance that dissolves
Atoms, ions, molecules
2) Solvent: substance in which the solute is dissolved
Usually water
Ex: Human blood
Solvent: Plasma (watery part of blood)
Solutes: Carbs, proteins, sugars, etc…

7. pH Scale pH scale measures the amount of H+ ions in a solution
Acid
Base
More H+
Few H+
neutral
Few OH-
More OH-
Lemons
Soft drink
Milk
Blood
Baking soda
Ammonia
pH scale measures the amount of H+ ions in a solution
1 minute: Discuss with your neighbor:
Which base has the most H+ ions?
Which substance has the fewest H+ ions?
Which is the strongest acid?
blood
Ammonia
Lemons

8. pH Scale pH scale measures the amount of H+ ions
Some molecules release H+ ions when dissolved
H+ ions accumulate (acids)
Acidic solution
Substance A H+ H+ H+ H+ H+ H+ H+ H+ H+

9. pH Scale pH scale measures the amount of H+ ions
Some molecules release H+ ions when dissolved
H+ ions accumulate (acids)
Some molecules release OH- ions when dissolved
OH- ions accumulate (bases)
Basic (alkaline) solution
OH-
OH-
OH-
Substance B
OH-
OH-
OH-
OH-
OH-
OH-

10. pH Scale pH scale measures the amount of H+ ions
Some molecules release H+ ions when dissolved
H+ ions accumulate (acids)
Some molecules release OH- ions when dissolved
OH- ions accumulate (bases)
pH balance vital to life
Ex: Blood pH (7.4): Proteins break down outside normal pH

11. Blood pH Normally: Balance of H+ and OH- ions in blood (7.4 pH)
Alcohol abuse: Excess alcohol lowers blood pH (H+ ions accumulate)
Kidney removes excess H+
Can lead to kidney damage

12. Review
1) Vocabulary: Polar, Adhesion, Cohesion, High Specific Heat, Solution, Solute, Solvent, pH 2) Name 4 basic features of water. 3) Which water property explains that one atom is positively charged, while another is negatively charged? 4) How does cohension and adhesion differ? 5) Which is a stronger acid? Substance A with a pH of 5 or substance B with a pH of 3? 6) Which has more H+ ions? Substance A with a pH of 5 or substance B with a pH of 3? 7) Which has more OH- ions? Substance A with a pH of 5 or substance B with a pH of 3? 8) How does a solute differ from a solvent? 9) What is the solute and solvent of blood?