Atoms: Basic building block of matter.

Made up of three subatomic particles: Protons + in the nucleus Neutrons neutral in the nucleus Electrons --- electron shell

Elements: Substance made up of all one type of atom. Six most common elements found in living organisms: C, H, N, O, P, S

Molecules/compounds: Two or more atoms bonded together.

1. Made up of two hydrogen atoms bonded to one oxygen atom. 2. Atoms bond to form an angular molecule

3. Water is classified as a polar molecule. Polar because like the Earth or a bar magnet it has a partial positive and a partial negative end. + -

Opposites attract:

Therefore, one molecule of water’s positive end is attracted to another molecule of water’s negative end giving water many unique properties

-1. Is an inorganic molecule -Contains no carbon -2. Made up of two hydrogen atoms and one oxygen 3. -forms an angular molecule 4. - Is a POLAR MOLECULE -has a + and a – end -5. Covers 75% of the Earth’s surface -6. Makes up 70% to 80% of a living organism + -

7. -Occurs in three phases -Solid -molecules have a small amount of energy -a little movement (just vibrating) -Liquid -molecules gain some energy and some movement -Gas -molecules gain a lot of energy and a lot of rapid movement (enough to escape the surface )

Experiment #1: What is density? -mass / volume Density of water? 10g / 10 ml = 1 g/ml 500g = 2 g/cm3 250 cm3 500 g = 0.2g/cm cm3

Saltwater is denser than freshwater because there is more mass per unit of volume due to the salt.

Experiment #2: Water Alcohol

Density: Mass/Volume Water in it’s solid form is less dense than its liquid form. But why?

Again, WHY ? When frozen, the water molecules slow down and due to their polarity they will line themselves up + to – end thus taking up more volume and lowering it’s density.

O H O - HH + H H H H O O Solid Liquid

Experiment #3: What is cohesion? -waters attraction to other water molecules

Cohesion of water molecules causes high surface tension. This means more force is needed to break the surface.

- Due to the fact that water is a polar molecule and opposites attract.

What is adhesion? -waters attraction to other types of molecules (like the paper)

Adhesion and cohesion are the two properties that allows water to move up a plant against the pull of gravity.

Experiment # 5 Sodium (Na) and Chloride (Cl) form an ionic bond = Sodium Chloride (NaCl)…table salt Water dissociates NaCl… Hydrogen atoms interact with chloride(--) Oxygen atoms interact with sodium(+)

Experiment #6:

Dissolves: The molecules of one substance are picked up and evenly distributed and surrounded by another type of molecule.

Experiment #7: Experiment #9: pH Levels 0-6 = __________ 7= ___________ 8-14= _____ __________

- 2 or more substances combined but not chemically. -each substance retains it’s own properties. -each substance can be separated from the other. Examples???????

- Suspensions - Solutions

A substance is mixed with water and the 2 substances separate. The less dense substance is “suspended above” the more dense substance. Example: Oil and water

One substance dissolves into another substance. Examples: Kool aid Salt water

Parts of a solution: Solvent: Substance doing the dissolving. (water) Solute: Substance being dissolved. (salt) Solution: Created when the solute DISSOLVES in the solvent. (salt water)

Water is known as the Universal Solvent. -dissolves more substances than any other solvent including all items that need to be dissolved in living organisms.

Aqueous solution: water is the solvent Saline solution: salt is the solute Tincture: Alcohol is the solvent

Acids, Bases and Neutral

 HCl is Hydrogen Chloride › H is +1 and Cl is – 1 therefore it is neutral › Not dangerous to us and our tissues › When HCl is dissolved into water, the H and Cl ions separate.  HCl is now known as Hydrochloric Acid › It is now very dangerous to us and our tissues

NaOH is Sodium Hydroxide Na is +1 and OH is – 1 therefore it is neutral Not dangerous to us When NaOH is dissolved into water, the Na and OH ions separate. NaOH, sodium hydroxide is now very dangerous to us and our tissues

A substance that release no +H or –OH ions when dissolved in water A substance that releases and equal amount of both the +H and the – OH ions and they cancel each other out. OR

-measures the strength and weaknesses of an acid (%H+) and of bases (%OH-) -based on a scale of 0 to 14

When an acid and a base of equal strength are mixed and cancel each other out creating a neutral substance. HCl + NaOH ----  NaCl + HOH Strong Strong neutral neutral acid base no H or OH H = OH

A substance which guards against shifts in the pH level. Our blood is an example of a buffer. Blood uses extra H+ and OH- ions substances to help resist pH changes in our body.