Presentation on theme: "Why Study Chemistry in Biology?. I. The Atom A. Definition: smallest particle of an element."— Presentation transcript:
Why Study Chemistry in Biology?
I. The Atom A. Definition: smallest particle of an element
B. Composition Subatomic Particle ChargeMassLocation Proton+11Nucleus Neutron01Nucleus Electron1/1840 the mass of a proton Orbiting nucleus
Location of Electrons outermost electrons participate in BONDING
II. Elements A. Definition: substance that cannot be broken down into other substances B. Biologically important elements i. Major: C H O N P S (Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur)
Bohr Atomic Model
DO NOW Why if atoms have so much space can we be solid? Why if atoms have so much space can we be solid?
A. Compound definition: a substance containing two or more elements in a fixed ratio –Ex: H 2 O, NaCl, CO 2 III. Chemical Compounds
Atoms want to fill their outer energy levels to be To do this, they will meet up with other atoms and either or electrons
i.Atoms share electrons
Examples of covalent molecules
ii. Ionic Bonds: gimme’ that electron! Atoms transfer electrons, becoming (+) or (-) charged The attraction brings them together –Ex: Na+ and Cl- = NaCl!
JOKE- Don’t Have to write this. A NEUTRON walks into a diner and sits down to order a meal. When the waitress brings the food over the neutron says “Can you bring the check? I am in a hurry!” The waitress replies, “Don’t worry about it, there is NO CHARGE for you.”
JOKE- Don’t have to write this. Two atoms walk down the street and collide. One atom says to the other, “Are you okay?” The second atom replies, “I think I lost an electron.” The first atom says, “Are you sure?” The second one says, “Yeah, I’m POSITIVE!”
iii. Molecules definition: two or more atoms held together by COVALENT bonds
LIFE DEPENDS ON THE UNIQUE PROPERITIES OF WATER V. WATER
Questions to think about Why do put salt on the roads? Why do we add salt to a pot of pasta water? At a higher altitude why must we cook “boil” something longer?
A.Human Composition: Cells are 70–90% water
B. Plant Composition As much as 95% plants can be made of water
C. Formula: H 2 O
D. Bonds: i. Hydrogen bonds: Hydrogens from one water molecule are ATTRACTED to the oxygen of ANOTHER water molecule: they develop a weak bond
i. Cohesion 1. Definition: Water “sticks” to each other Ex.: Surface tension 1-inch paperclip over-filled water 3oz Dixie cup
Jesus Christ Lizard
ii. Adhesion 1. Definition: Water molecules attracted to other molecules. 2. Ex. In trees/plants water goes against gravity Called capillary action
Water is the a Universal Solvent Water is able to dissolve other Polar & ionic compounds when mixed by causing the ions to break away and surround them. Water dissolves Salt (Na + Cl - )
iii. Temperature and Water When you heat molecules move faster When you cool molecules move slower Water takes more energy to heat because energy must break hydrogen bonds Boiling Point: 100 o C / 212 o F
Does water boil faster if you add salt to it? Water Boils when it has enough energy for the molecules to leave
Freezing Point What would happen if our oceans did not have salt in them? Why do we put salt on our roads? Why at effect does salt have on FREEZING POINT? 0 o C or 32 o F
Why is this important for life? Water Boiling Point Ethanol Boiling Point
Why are higher altitude must we cook “boil” something longer?
Why do we need salt in our ice, when making ice cream? Watch Video Why do we need salt in our ice, when making ice cream? Watch Video
LOW DENSITY OF ICE Density- amount of matter in a volume In most substances the solid state is more dense than the liquid state Water is the opposite ICE IS LESS DENSE THAN WATER and will FLOAT
LOW DENSITY OF ICE WHY? Hydrogen bonds in ice (solid) keep molecules spaced out
LOW DENSITY OF ICE Floats Ice insulates the liquid water below allowing life to persist