Chemistry
Final Study Guide
- Scientific Method
Observe, Hypothesis, Experiment, Conclusion, Retry
Experiment
- Accuracy vs. Precision
Accuracy: the quality of being
near to the true value
Precision: the quality
of being reproducible in amount or performance
- Percent Error:
Accepted –
Experimental divided by Accepted multiplied by 100
Chapter One:
- Gases in Breath:
Nitrogen (most
abundant), Oxygen and Argon
Very little abundance
Carbon-dioxide and water
- Definitions of PM2.5
and PM10
2.5
diameter of a pollutant in microns/micrometers
10
diameter of a pollutant in microns/micrometers
- Conversions
between PPM and Percentage
Factor of 10,000
Example: convert 9ppm
to percentage
1. 9
divided by 1,000,000
2. 9
x 10-4%
- AQI –
Calculated: (Troposphere Ozone, Particulate Matter, CO, SO2, NO2)
Air Quality Index:
Colors indicate the air quality in certain areas
Air Pollutants: Risk
Assessment
Evaluating specific
data and making predictions in an organized manner about the probability of
occurrence
Toxicity: Intrinsic health
hazard of a substance
Exposure: Amount of the
substance encountered
- Why are exposures
to pollutants limited? How is the limit decided?
Pollutants are bad for
our health. Limit decided by toxicity, abundance, and the amount of exposure.
(BAD gases: carbon
monoxide, ozone, sulfur oxides, nitrogen oxides and particulate matter)
- Levels of
Atmosphere and differences in air in each part of atmosphere:
1. Troposphere:
Lowest region
Between 1 and 2
is the Ozone Layer
2. Stratosphere:
Middle Region
3. Mesosphere:
Highest Region
- Naming Compounds:
|
HYDROCARBONS |
Mother Eats Peanut Butter |
|
Methane |
CH4 |
|
Ethane |
C2H6 |
|
Propane |
C3H8 |
|
Butane |
C4H10 |
Diatomic Molecules: Halogens: Group 7 and
8 also including oxygen nitrogen and hydrogen
- Naming Compounds:
Ionic and Covalent
Ionic Bond: Chemical
bond formed by the attraction between oppositely charged ions
Covalent Bond: Chemical
bond in which two electrons are shared by the atoms involved
- Reactants and Products in Chemical reactions:
Chemical Reactions: characterized by the
rearrangement of atoms when reactants are transformed into products
- Balancing Equations:
- If an element is
present in just one compound, on each side balance it first
- Balance anything that
exists as a free element last
- Balance polyatomic ions
as a unit
- Check – same
number of atoms and same total charge (if any) on both sides
- Periodic Table:
- Organization:
- Properties of non metals, metals, metalloids,
and noble gases
Metals: elements that are shiny and conduct
electricity and heat well
Non-Metals: elements that have varied appearances
and donΥt conduct well
Metalloids: Between Metals and Non-metals do not
fall clearly into either group.
Noble Gases: Elements that are inert and do not
readily undergo chemical reactions.
- Sources of Pollutants: Indoor and Outdoor
Indoor: Cigarettes, fireplace, incense, Windex,
radon
Outdoor: Carbon monoxide, Car emissions Sulfur
dioxide (coal burning)
Chapter 2
- Ozone:
An atmospheric gas found in
both the troposphere, and the stratosphere. (Lower Stratosphere)
- Allotrope:
Allotropes: two or more
forms of the same element that differ in their chemical structure and therefore
in their properties.
- DU:
Dobson Unit: 1mm=100 Dobson
unit
- Ozone Layer:
The stratospheric region of
maximum ozone concentration
- Atoms:
- Structure:
Nucleus, Protons, Electrons:
Nucleus: Composed of Neutrons and Protons
Protons: Positively charged particles
Neutrons: Neutrally charged particles
Electrons: Much smaller mass than a proton, but with
a negatively electric charged particle
- Periodicity of elements in table Valence
Electrons (OUTER ELECTRONS)
- Mass Number and Atomic Number:
- Isotopes
- Covalent Bonds Two electrons that are shared constitute a
covalent bond
- Isotope: Different number of neutrons, the mass
will either go up or down
Lewis Structure:
- Single, Double, Triple Bonds:
- Single: Only one pair
of shared electrons
- Double: Two pairs of
shared electrons
- Triple: Three pairs of
shared electrons
- Resonance:
- Light Waves:
Wavelength, Frequency and
the mathematical relationship between the two
Relationship: Wavelength increase,
Frequency Decreases
- EM SPECTRUM:
EM Spectrum Ranges from short to high
X-rays and gamma rays
- Order Of Regions:
IR, Visible, UV
- Numbers for Visible Region
400-700nm in the visible region
- Photon, Quantization, Math relationship between
the two
Energy and Frequency are directly related!
Photon: Individual bundles of energy
Quantization: Energy Distribution Many steps not continuous
- Oxygen/ Ozone Sunscreen
Ranges of Wavelength that absorbed by O2
and O3
O2 takes a shorter wavelength to
break it then O3
The Chapman Cycle:
Natural
steady-state reactions for stratospheric ozone.
- Biological Effects of Radiation:
Skin
and Eye Protection: From cancer
- Stratospheric Ozone Destruction:
Ozone
Hole: an area of the ozone layer (near the poles) that is seasonally
depleted of ozone (DU LEVEL <220) OZONE HOLE
Free radicals: Cause the Ozone Hole
Pulls oxygen away from Ozone
Natural Cause of Ozone Destruction: Water Vapor
Man-Made cause of Ozone Destruction: CFCs (CHLORINE FROM THEM)
Ozone Destruction: Oxygen breaks apart!
Montreal Protocol: Limit/band the use of CFCs
Temporary Replacements: HCFCs
:Break
apart in lower atmostphere so it does not cause damage
Chapter 3
- Fossil Fuel: Decayed plants and animals that
can create fuel (combustion burns them turned into fuel)
- Largest case of
reservoirs is fossil fuels.
Are they largest source of CO2 that is man made. Largest
non man made cause is the ocean
- Global Warming: Warming of the earth by
trapped atmospheric radiation
- Greenhouse Gases: Carbon dioxide, Water
Vapor, and Methane (CH4)
- Energy Balance of radiation to earth and away
from earth: Hidden in atmosphere
- Enhanced greenhouse effect: Bad affect of global
warming, in which gases are trapped and return more than 80% of the heat
that is radiated by the earth
- 80% of gases kept in Earth by atmosphere!
- How do we know CO2 concentration
from long ago? Ice Core samples, Volcanic gases
- Ice Core Drilling,
Volcanic Gases for more recent data way we know about CO2
- Photosynthesis: Takes carbon-dioxide
and converts it to oxygen (COO2)
- Global temperature: change reflects changes
in CO2 concentration
- Carbon Dioxide GOES UP affects the
temperature: TemperatureGOES UP as result
Molecular
Geometry: 3D version of a Lewis structure
VSEPER:
VALENCE SHELL ELECTRON PAIR REPULSION
RULES:
Vibrating
Molecules and greenhouse effect:
Vibrates Green House effect: causes greenhouse
effect:
Infrared
(heat) radiation emitted by Earth gets absorbed in atmosphere by vibrating
molecules!
Only some gases are greenhouse gases because only
some get vibrated.
Vibrating moleculesvibrate when they absorb energy
What happens
when different frequencies of light hit molecules?
Percent
transmittance: Amount that goes into the atmosphere
When different frequencies of light hit molecules vibrational states are quantized:
Lower frequency to spin, Higher to vibrate
Carbon Cycle: Trees and Oceans absorb it!
Largest sink: Fossil fuels (Biggest MAN MADE source)
Average Atomic
Mass: the mass of an atom of a chemical element
expressed in atomic mass units
(Abundance in decimal
of isotope A) X (isotope mass A)
(Abundance in decimal
of isotope B) X (isotope mass of B)
+ etc.
EXAMPLE:
Abundance
Relative Mass
0.005%
234.0409
(0.005) (234.0409) +
0.720%
235.0439
(0.720) (235.0439) +
99.275% 238.0507 (99.275) (238.0507) = 238.0289 ATOMIC MASS
Avagados Number: 6.022X1023‑ Molar Mass: Mass on
periodic table of elements
MASS
PERCENT % element (number of atoms) (atomic weight) x 100 divided by mass of
entire compound
Empirical
Formula: Can determine ratio of atoms more easily
Green House Gases:
α CH4 , N2O
and O3 (OZONE)
GWP : Global
Warming Potential : Factors in considering which greenhouses gases to be targeted?
1. Global warming potential
2. Relative Abundance
3. Atmospheric lifetime
CO2=1 ALL other gases measured relative
to it
Gases with short atmospheric lifetime not assigned
GWP
Computer modeling:
α Vital to being able to
predict climate change
α Important for models are:
Oceans, solubility of CO2, green house affect
α Temp goes up solubility goes
down
WHAT
TO DO ABOUT TEMPERATURE!
-
REDUCE IMPORTANCE ON
FOSISL FUELS
Kyoto Protocol:
Annex countries:
Disagree
with Kyoto Protocol
Annex
1: Industrial Countries
Annex
2: Developed Countries
Annex
3: Developing
US: Has not ratified this
- Hurt economy
- Lack of restrictions
for developing countries
Global Warming VS. Ozone Depletion:
The depletion of ozone does
not affect global warming!
UV has other damaging
effects BUT does not warm earth!
Second Law: the Entropy (randomness) of the world
continues to increase
Chapter
5: WATER
Water
comes from aquifers: great pools of water trapped 50-500 ft below the surface
Reasons
water is good for you:
- Water carries
materials into and out of our bodies. But water from natural resources
are never pure
Concentration:
Ratio of the amount of
solute to the amount of solution
Polar
molecule: A covalent bond, in which the electrons are not equally displaced or
shared toward the electronegative atom
Water
is a polar molecule: It stabilizes molecules, as they break apart
Electro
negativity: Measure of an atomΥs attraction for the electrons it shares in a
covalent bond
Hydrogen bonding: H bond
shared in covalent bond
Intermolecular force: force
that exists within a molecule
Water: Hard (contains high
concentrations of calcium and magnesium) Soft (lower concentrations of these
ions)
Aqueous solutions:
electrolytes (conducting) and non-electrolytes (non conducting)
Metals:
FORM Cations lose electrons
(metal)
FORM Anions gain electrons
(non metal)
Ion Compounds:
made up of electrically charged ions, arranged in patterns
Chapter 6:
ACID RAIN!
Titration
Chart
Chapter
8: Energy from electron transfer
Redox Reactions:
REDUCTION AND
OXIDATION REACTIONS!
- Reduction: Shows reactant that gains electrons
- Oxidation: Shows reactant that loses electrons
- (Oil Rig)
- ANODE: the electrode
where oxidation takes place
- CATHODE: the electrode
receives the electrons sent from the anode through the external circuit
- Half reaction:
is a type of chemical equation that shows the electrons either lost or
gained
Galvanic Cells: Is a device that converts the energy
released in a spontaneous chemical reaction into electrical energy
Electrolytic cell: one in which electrical energy is
converted into chemical energy
Photovoltaic cell: Converts radiant energy to
electrical energy
Semiconductor: Materials that do not normally
conduct electricity well, but can do so under certain conditions such as
exposure to sunlight.