1. KEY CONCEPT Water’s unique properties allow life to exist on Earth.

2. Review
Ion- an atom that has gained or lost one or more electrons.
Molecule- is two or more atoms held by covalent bonds.
Ionic bonds- forms through the electrical force between oppositely charged ions.
Covalent bonds- forms when atoms share a pair of electrons.
Compound- is substance made of atoms of different elements bonded together in a certain ratio.

3. Question
When you are thirsty, you need to drink something that is mostly water. Why is the water you drink absolutely necessary?

4. Life depends on hydrogen bonds in water.
Water is a polar molecule.
Polar molecules have slightly charged regions. O H _ +
Nonpolar molecules do not have charged regions.
Hydrogen bonds form between slightly positive    hydrogen atoms and slightly negative atoms.

5. Hydrogen bonds are responsible for three important properties of water.
high specific heat- The amount of heat or energy required to raise a unit of mass of a substance 1 degree Celsius
Cohesion- The attraction among molecules of a substance. The cohesion between water molecules make them stick together.
Adhesion- attraction of molecules to a different substance. Water sticks to other surfaces. This includes Capillary action.

6. Summary
Question:
How are Hydrogen bonds similar to ionic bonds?
Summary:
Write a 3-5 sentence summary about what we talked about today.

7. Many compounds dissolve in water.
A solution is formed when one substance dissolves in another.
A solution is a homogeneous mixture.
Solvents are substances that are present in a greater amount and dissolve other substances.
Solutes substance that dissolves in a solvent.
solution

8. “Like dissolves like.”
Polar solvents dissolve polar solutes. (Like water and salt)
Nonpolar solvents dissolve nonpolar solutes. (
Polar substances and nonpolar substances generally remain separate. (like oil and water)

9. Summary
Question: Look at the ingredients of Dr. Pepper and tell me what the solutes and solvents are. Make a column for each.
Dr Pepper Ingredients: carbonated water, sugar/glucose-fructose, colour, phosphoric acid, artificial and natural flavours, sodium benzoate, caffeine.

10. Some compounds form acids or bases.
An acid releases a hydrogen ion when it dissolves in water. (HCL or hydrochloric acid)
high H+ concentration
pH less than 7
more acidic
stomach acid pH between 1 and 3

11. A base removes hydrogen ions from a solution
A base removes hydrogen ions from a solution. (CaCO3 or calcium carbonate, what’s in TUMS)
low H+ concentration
pH greater than 7
bile pH between 8 and 9
more basic

12. A neutral solution has a pH of 7. (distilled water)
pure water pH 7