Bio Test 1
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What is an element?
Basic material that cannot be broken down by a chemical reaction.
A compound is
Two or more elements in a fixed ratio.
What four elements make up ___% of all living things?
- O- Oxygen
- C- Carbon
- N- Nitrogen
What is an atom?
Smallest unit of matter that still retains the properties of an element.
What are subatomic particles, where are they located, and what is their funtion?
Neutrons - nucleas isotopes
Protons- nucleas type of element
- Electrons- shells/orbitals
Describe an ideal atom.
Ideal atom would have equal number of protons, neutrons, and electrons
Isotope vs Ion
Isotope is the same element with a different number of neutrons.
- An ion has an unequal number of e- and protons.
- - Cation - more protons + charge
- - Anion - more electrons - charge
How are electrons distributed around an atom.
Valence shells. First shell contains two electrons, all the rest need 8 per shell. if the shell is full it won't react, if not full it will react.
Explain covalent bonding.
2 atoms sharing pairs of electrons.
Non-Polar - equal sharing, no charge
Polar - Unequal sharing due to electronegativity (attraction for electrons). Charge is partial pos or partial neg.
Explain Ionic bonding.
Two atoms Transfer electrons. Both atoms have charges, are elctronegative, always forms compunds.
Describe Hydrogen bonding.
A hydrogen atom bonds with a polar molecule. Very weak bonds, but many together is strong. Bonds with O, N,
Van Der Waals interactions. Explain.
Weak chemical bonds. Assymetrical distribution of electrons such as dispersion forces. Dipole-dipole bondings is also included.
SHAPE = FUNCTION
Valence electrons, change shape...calter function.
What is the bilogical medium for all life on Earth?
How is water structured?
POlar molecule with polar covalent bonds. Oxygen has a partial negative charge, while the hydrogen has a partial positive charge. Oxygen is stronger, more electronegative, so the H electrons spend more time around oxygen giving it a more negative charge.
Four Properties of Water:
- 1. Cohesion
- 2. Moderation of temperature
- 3. Expansion upon freezing. (water is less dense as solid)
- 4. Universal solvent of life.
Explain water's high specific heat.
- Specific Heat is amount of heat needed to raise or lower 1g of substance 1 degree celsius. Water is unusually high.
- Ex. Boil pan of water. Pan is extremely hot (low specific heat) when water is lukewarm (high specific heat).
How does water moderate temperature?
Absorbs heat from air that is warm, releasing already stored heat to the cooler air.
Evaporative Cooling. Explain.
Evaporative cooling occurs because the hottest particles turn to gas and escape surface, leaving the coolest particles behind.This stabilizes temperature.
Heat of Vaporization.
Heat that must be absorbed for 1g of substance to turn to gas.
What are the different components of a soluton?
Solute: Dissolved by solvent
Solvent: the dissolving agent
What is a hydration shell?
Example is water surrounding a Na atom. This breaks ionic bonds by surroung agent. Molecules must be polar.
What is an acid? A base?
An acid is a subtance that will donate or increase hydronium or (H+) to a solution.
A base is a substance that reduce the amount of H+ hydronium ions by adding OH-.
Explain pH and pH scale
Used to determine how acidic or basic a solution is. Based on a logarithum from pure water. Less than 7 is acidic more than 7 is basic. Neutral is 6-8. Each level is 10x stronger.
What is a buffer?
A buffer is a solution, usually weak acid or base, that will stabilize changes in a pH. It does this by absorbing or releasing hydronium (H+) ions.
What bonds can Carbon form?
Carbon can form single, double, or triple bonds. This varies length of carbon skeleton (linear or rings)(branched or unbranched).
What are hydrocarbons?
Consist only of hydrogen and carbon. responsible as fats, oils
Release alot of energy
What is an isomer?
Compounds with same molecular formula but different structures and different properties. Bigger the structure, greater number of isomers.
What is a structural isomer?
Different bonding pattern
What is a geometric isomer?
- Same bond arrangement, but different spatial arrangements.
- Cis Trans
- Cis- same side
- Trans- Opposite
What is an enantiomer?
Mirror images of each other. (like a left and right hand).
What is ATP?
- Primary energy source for cell.
- Strong potential to react with water.
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