1. Water

2. H2O Basics + +
Polar: part of a molecule is slightly positive, while another part is slightly negative
Oxygen: 8 protons, 8 electrons
“Hogs” electrons from Hydrogen after bonding with Hydrogen = 8 protons, 10 electrons
Negative charge
Hydrogen: 1 proton, 1 electron
After bonding with Oxygen = 1 proton, 0 electrons
Positive charge 1 1 1 1 1 2 6 1 5 2 3 4 -

3. H2O Basics H+ H+ O- O- H+ O- H+ H+ O- O- H+ H+ O- O-
Polar: part of a molecule is slightly positive, while another part is slightly negative
Oxygen: 8 protons, 8 electrons
“Hogs” electrons from Hydrogen after bonding with Hydrogen = 8 protons, 10 electrons
Negative charge
Hydrogen: 1 proton, 1 electron
After bonding with Oxygen = proton, 0 electrons
Positive charge
Creates hydrogen bonds where one water molecule sticks to another H+ O- H+ O- H+ O-
Hydrogen bond H+ O- H+ O-

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

5. Practice:
Draw 4 water molecules
Draw their bonds with each other
Label oxygen & hydrogens’ charges (+, -)

6. It takes a lot of energy to change water’s temperature
Water Properties
High specific heat: Resists temp changes
Much energy needed to break water bonds
It takes a lot of energy to change water’s temperature

7. Water Properties High specific heat: Resists temp changes
Much energy needed to break water bonds
Helps to maintain a constant body temp
The weight of our bodies is mostly water. Our body temperature doesn’t change much even when we exercise.
If our temperature changes too much, we feel sick.

8. 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
Why can this this paper clip stay on top of water?
It is not heavy enough to break the hydrogen bonds that hold the water molecules together.

9. 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
meniscus 35
29 ml 25
25 ml 15 5

10. 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
Usually in greater quantity than solute
Solution S U G A R K O O L A I D
Crystal light…
Kool-aid…
Country Time Lemonade…

11. 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
Usually in greater quantity than solute
Ex: Human blood
Solvent: Plasma (watery part of blood)
Solutes: Carbs, proteins, sugars, etc…
Plasma
WBCs & Platelets
RBCs

12. 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

13. 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+

14. 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-

15. pH Scale pH scale measures the amount of H+ ions
Acid
Base
neutral
Blood
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

16. 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

17. Review
1) Vocabulary: Polar, Adhesion, Cohesion, High Specific Heat, Solution, Solute, Solvent, pH, Hydroxide 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 cohesion and adhesion differ? 5) How does the water in our cells help to maintain homeostasis? 6) Which is a stronger acid? Substance A with a pH of 5 or substance B with a pH of 3? 7) Which has more H+ ions? Substance A with a pH of 5 or substance B with a pH of 3? 8) Which has more OH- ions? Substance A with a pH of 5 or substance B with a pH of 3? 9) How does a solute differ from a solvent? 10) What is the solute and solvent of blood?