why study chemistry in biology?. i. the atom a. definition: smallest particle of an element
TRANSCRIPT
I. The Atom
A. Definition: smallest particle of an element
B. Composition
Subatomic Particle
Charge Mass Location
Proton +1 1 Nucleus
Neutron 0 1 Nucleus
Electron -1 1/1840 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)
Radioactive Isotopes
Bohr Atomic Model
•Atoms Space
DO NOW
•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: H2O, NaCl, CO2
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:H2O
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-inchpaperclip
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 oC / 212 oF
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 oC or 32 oF
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
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