Exam 2 Flashcards
1
Q
The chemical process of burning that is, the reaction of fuel with oxygen to release energy in the form of heat and light
A
combustion
2
Q
Steps to producing energy from coal
A
- combustion
- use heat from combustion to boil water in a closed high pressure system (compresses water vapor to create steam)
- generates electricity as steam goes past turbine causing it to spin.
3
Q
How to increase potential energy
A
heavier and higher
4
Q
How to increase kinetic energy
A
heavier and faster
5
Q
The energy of the reaction of the product
A
chemical energy
6
Q
What makes a good fuel
A
higher potential energy means the better the fuel, higher efficiency mean less fuel have to be burned to generate the same amount of energy and that less carbon dioxide and other pollutants would be emitted
7
Q
Energy neither created or destroyed just changes forms
A
First law of thermodynamics
8
Q
How to calculate net efficiency
A
% net efficiency = (electrical energy produced / heat from fuel) * 100
9
Q
Efficiencies of most fossil fuel power plants
A
35-50%
10
Q
How much energy from gasoline used to move vechile
A
15% used to move vechile
60% lost from internal combustion of engine
11
Q
A measure of how much energy gets dispersed in a given process
A
enthropy
12
Q
The enthropy of the universe is constantly increasing
A
2nd law of thermodynamics
13
Q
Why is coal better than wood
A
contains higher percentage of carbon and lower percentage of oxygen (more oxygen a fuel contains the less energy per gram it release on combustion, lower potential energy scale)
14
Q
Coal grades
A
lignant
bituminous
anthracite - high carbon and low sulfur = most desirable coal
15
Q
To remove sulur and other minerals impurities from the coal before it is burned
A
coal washing
16
Q
to convert coal to a mixture of carbon monoxicde and hydrogen. Gas burns at a lower temp thus reducing the generatio of nitrogen oxides
A
gasification
17
Q
chemically remove SO2 before it goes up in the smokestack
A
web scrubbing
18
Q
Pros and cons of coal
A
pros - available throughout the globe, high net energy, infustructure is there
cons - dangerous and sometimes expensive to excavate, environmental harm, dirty fuel, produces CO2
19
Q
Pros and cons of petroleum
A
adv= advantage of being liquid = easily pumped to the surface and transported via piplines to refineries, yield 40-60% more energy per gram than coal (48kJ/g vs. 30 kJ/g), relatively clean (no sulfer dioxide CO, or nitrogen oxides), waste is used as “feedstocks” to produce other produces such as plastics,
cons - produces CO2, lags between oil discovers, using faster than finding, oil spills, oil sands, hydraulic fracking can poison water,
20
Q
What is oil made up of
A
hydrocarbons
21
Q
A measure of the average kinetic energy of the atoms and/or molecules present in a substance
A
Temperature
22
Q
The kinetic energy that flows from a hotter object to a colder one
A
Heat
23
Q
A device used to experimentally measure the quality of heat energy released in a combustion reaction
A
calorimeter
24
Q
The quantity of heat energy given off when a specificed amount of a substance burns in oxygen
A
heat of combustion
25
units of heat of combustion
kJ/mol kJ/g kcal/mol kcal/g
26
A term applied to any chemical or physical change accompanied by the release of heat
exothermic
27
sign of an exothermic reaction
negative signifies the decrease in potential energy going from reactants to the products ( higher potential energy of a fuel the more heat it releases)
28
Fuels with th highest heats of combustion are called
hydrocarbons
29
As the ratio of hydrogen to carbon decreases...
the heat of combustion decreases
30
As the oxygen in the fuel increases...
the heat of combustion decreases
31
Term applied to any chemical or physical change that absorbs energy
endothermic
32
Examples of endothermic processes
natural occurring, involve electrical discharge, a high-energy photon or a high temperature (photosynthesis)
33
Energy change of an endothermic reaction is always
positive the potential energy of the products is higher than that of the reactants
34
Energy required to break bonds
If energy required to break the bonds in the reactants is greater than the energy released when the products form (endothermic) = energy is absorbed
If bond making energy of products is greater than the bond breaking in the reactants then the net energy change is (exotermic) energy is released by the reaction
35
The amount of energy that must be absorbed to break a specific chemical bond
bond energy
36
A process that breaks large hydrocarbon molecules into smaller ones by heating them to a high emperature making the molecules smaller and more economically important
Thermal cracking
37
Problem with thermal cracking
energy required to produce the high termerature
38
A process in which catalysts are used to crack larger hydrogarbon molecules into smaller ones at relatively low termperature
Catalytic cracking
39
Molecules rearranged usually starting with linear molecules and producing ones with more branches. More highly brancged molecules burn more smoothly in automobile engines
Catalytic reforming
40
Molecules with the same molecular formula but with different chemical structure and different properties are called
isomers
41
The energy necessary to initiate a chemical reaction
activation energy
42
How to Lower activation energy
Increase temperature,
reactions that happen faster have lower activation energy
Catalyst can lower activation energy
43
Pros and Cons of ethanol
Pros - cleaner energy, renewable, lower CO2
Cons - contains more oxygen so has a lower energy content (cellulose) , can take up food sources, lots of agriculture needed, can corrode fuel tanks if not in the right amount
44
How ethanol made
fermentation. alchol - a hydrocarbon substituated with one or more -OH groups bonded to its carbon atoms
45
A distinctive arrangement of a group of atoms that imparts characteristics properties to the molecules that contail this group
functional group
46
Biodisel
made from veg oils, and animal fats, wasted cooking oil, triglicerides, and fats
47
Pros and cons of biodesil
Pros - renewable, recycled oil,
| Cons- can not go strait into tank, release CO2,
48
Properties of Water
liquid at room temperature
low molar mass 18 g/mol
high boiling point (100 C)
Water expands when it freezes
49
A measure of the attraction of an atom from an electron in a chemical bond ( the greater the difference in electronegativity the more polar the bond is)
Electronegativity
50
Polarity of water
partially neg on O
| partially pos on H
51
A covalent bond in which the electrons are not equally shared but rather are closer to the ore electronegative atom
polar covalent bond
52
A covalent bond in which the electrons are equally shared
nonpolar covalent bonds
53
Help predict if a bond is polar
-if molecule has only nonpolar bonds it must be nonpolar (H2)
= molecule contains polar covalent bonds it may or may not be polar, it depends on the geometry
54
An electrostatic attraction between a Hydrogen atom bonded to a highly electrognative atom (O, N, or F) either in another molecule or a different part of the same molecule. 1/10th as strong as covalent bonds and farther apart than covalent bonds
Hydrogen bonds
55
Why frozen water floats
It creates a crystal/ lattice structure when it freezes due to hydrogen bonds. This creates a lot of empty space in the ice lowering the density. (liquid water is more dense)
56
The mass per unit of volume
density
57
The quantity of heat energy that must be absorbed to increase the temperature of 1 gram of a substance by 1 degrees celcius
Specific heat
58
Water has one of the highest specific heats and a high heat capacity (makes it an execptional coolent)
B/c hydrogen bonds
59
How much of the water is fresh water
3%
60
How much of the water is salt water
97%
61
Break down of fresh water
lakes rivers and wetlands .3%
62
What we use water for
```
85% from fresh 15% from salt
IN US
50% industry
31% crop irrigation
12% homes, schools and businesses
```
Around the world
70% for irrigation
63
Estimates of the volume of fresh water used to produce particular goods or to provide services
water footprints
64
Water issues
global climate change, overconsumption and inefficient use, Contamination
65
How many people lack safe drinking water
Almost a billion
66
US EPA definition of a water contaiminant
Anything physical chemical biological or radiocationve that is harmful to human health or degrades the taste or color of the water (90 known substances)
Not all contaiminatnts found in water are regulated
67
The ratio of the amount of solute to the amount of solution
Concentration
68
Ways to express concentration
percent (per 100 grams of solution), parts per million, parts per billion and molarity
I ppm = 1mg solute / 1L water
69
A type of glassware that contains a precise amount of solution when filled to the mark on its neck.
volumetric flask
70
An apparatus that produces a signal to indicate the electricity is being conducted
conductivity meter
71
A solute that is nonconducting inan aqueous solutions ex sugar
nonelectrolyte
72
A solute that conducts electricity in an aqueous solutions ex NaCl
electrolyte
73
The chemical bond formed when oppositely charged ions attract
ionic bond
74
Composed of ions that are present in fixed proprtions and arranged in a regular geometric structure
ionic compounds
75
ionic bond
- transfer of electrons
| - between a metal and non metal (metals give up electrons and nonmetals gain electrons)
76
Two or more atoms covalently bonded together that have an overall positive or negative charge
polyatomic ion
77
How are aqueous solutions made
ions are separated and surrounded by water molecules. cations attracted to partially negataive O. Anions attracted to partially positive H.
78
Difference on how dissolvable something is
The size and charges of the ions, how strongly they attract to one another and how strongly the ions are attracted to water molecules (pg 240)
79
What happnens to covalent polar in water
molecules remain intact and disperse uniformly amoung H2O molecules. ex sugar
80
Attraction exists between the solvent molecules and the solute molecules or ions
Like dissolves like
81
Things that dissolve in water
ionic - salts (NaCl)
| polar covalent - ethylene glycol, ethanol, thyl alchol (-OH groups)
82
Compounds that help polar and nonpolar compounds mix
surfactants
83
Tendency of nonpolar compounds to dissolve into other nonpolar substances explains what with fish
how fish and animals accumulate nonpolar substances such as PCBs or pesticide DDT in their fatty tissue. (stored in nonpolar fat rather than polar blod)
84
The increase in concentraition of certain persistant chemicals in successively higher levels of a food chain
biomagnification
85
To ensure potable water to those who depend on community water supplies. Containments that may be health risks are regulated by the EPA. Controls pollution of lakes, rivers, and costal areas
Safe Drinking Water Act (SDWA)
86
The maximum level of a contaminant in drinking water at which no known or anticipated adverse effect on human health would occur. not a legal limit
Maximum Contaminant Level Goal (MCLG)
87
For known carcinogens the EPA has set the health goal to...
zero
88
The legal limit for the concentraition of a contaminent expressed in parts per million or parts per billion. range from 10 ppm to less than 1 ppb
Maximum Contaminant Level (MCL)
89
Water contaminents
Lead - acculates in bones and brain causing severe and permanent neurological problems. Irritability sleeplessness and irrational behavior. effect children bone mass and damage to brain can cause retardation and hyperactivity
Nitrate ion (NO3-) - can be converted into nitrite ion (NO2-) that limits blood ability to carry oxygen. can cause difficulty in breathing and possibly permanent brain damage from lack of oxygen
Biological agents - live in digestive tracts, diarrhea, cramps, nausea, and vomiting
90
1974 provided the foundation for educing surface water pollution. Established limits of the amounts of pollutants that industry can discharge removing over a billion pounds of toxic pollutants from US waters every year
Clean Water Act (CWA)
91
Water treatment
1. pass water through a filter
2. add aluminum sulfate and calcium hydroxide
3. clorination
92
A measue rof the amount of dissolved oxygen that microorganisms use up as they decompose organic wastes found in water. A low BOD indicates good water quality
Bioogical oxygen demand (BOD)
93
Contributors to BOD
Nitrates and phosphates
overabundance can lead to algal blooms that clog waterways and deplete oxygen from water.
Reduced oxygen can lead to fish kills
94
Any process that removes sodium chloride and other minerals from salty water thus producing potable water
desalinated water
95
A separation process in which a liquid solution is heated and the vapors are condensed and collected
distillation
96
Uses pressure to force te movement of water through a semipermeable membrane from a solution that is more concentrated to a solution that is less concentratid
reverse osmosis
97
Tech that removes pathogens from water. Limitation is that it does not remove chemicals
Point-Of-Use lifestraws
98
Cotton leaves a huge foot print BOD is equal to
raw sewage
it is better to use and generate substances that are not toxic
99
Do not flush prescription drugs
better to prevent waste than to treat or clean up waste after it is formed
100
A compound that releases hydrogen ion in an aqueous solution
acid
101
An acid that dissociates completely in an aqueous solution
strong acid (HCL, SO2 and NO2)
102
Irregular/weak acid or base break downs
263 CO2
264 NH3
269 CaCO3
103
An acid that dissociates only to a small extent in an aqueous solution
weak acid (carbonic acid)
104
A compound that releases hydroxide ions OH- in aqueous solution
base
| NH3, NaOH
105
Bases that dissociate completely in ater, such as NaOH
strong bases
106
A base that dissociates only to a small extent
weak base
107
A chmical reaction in which hydrogen ions from an acid combine with te hydroxide ions from a base to form water molecules
neutralization reaction
108
Neither acidic nor basic. It has equal concentrtions of H and OH.
Neutral solution
109
A number usually between 0 -1 that indicates the acidity for a solution les than 7 = acidic greater than 7 = base
pH
as pH decreases acidity increases
110
The lowering of the pH due to increasesd atmospheric carbon dioxide
ocean acidification
111
When pH of rain is lower than 5 we call it
acid rain
112
How to measure acidity of rain
250 sites of the National Atmospheric Deposition Program/ National Trends Network (NADP/NTN) sensor and 2 buckets
put near special ecosystems
113
Chemicals that cause acid rain
CO2
Sox (2,3) and Nox (1,2)
pg 273
pg 274
114
The wet and dry forms of delivery of acids from the atmosphere to the surface of the earth
wet - rain snow and fog
dry - aerosols ammonium nitrat, ammonim sulfate can cause haze
acid deposition
115
Levels of SO2 emission vary
depending on how much coal burning electric utility plants are equipt
coal problem 276
116
percentage of SO2 emissions
87% fuel combustion
10% industrial processing
2% transportation
1% miscelllaneous
117
percentage of NOx emissions
51% transportation
37% fuel combustion
8% industrial
4% miscellaneous
118
How NOx emissions occur
temperature gets really hot in engine and N2 can react with O2
NO2 hihly reactive red brown gas with nasty odor can turn into nitric acid
pg 278
119
The compounds of nitrogen that cycle through the biosphere and interconvert with each other
reactive nitrogen
ex. aminies NH2
120
Bacteria remove nitrogen gas from the air and convert it to ammonia
nitrogen fixing bacteria
121
Nitrogen cycle things that produce nitrogen
producing food
| nitrates in fertilizers
122
The process of converting ammonia in the soil to the nitrate ion
nitrification (280)
123
the process of converting nitrates to nitrogen gas (releases N2)
denitrification
124
A set of chemical pathways whereby nitrogen moves through the biosphere
nitrogen cycle
125
N2 + 3H2 -> 2NH3
Haber-Bosch process
allows economical production of ammonia which in turn enables the large-scale production of fertilizers and nitrogen based explosives
126
Increase of reactive nitrogen from burning fossil fuels and fertilization parrellel
growth of world population
127
Natural sources of SO2 emissions
volcanos
| oceans (marine organisms)
128
Natural sources of NO
lightnig strikes
forest fires
bacteria converting nitrogen gas into nitrogen oxides
129
Anthropogenic SO2 and NOx
SO2 twice as much as natural
| NOx 4 times as much (increased 1950s then started decreasing 1970s due to Clean Air Act Ammendments)
130
National Acid Precipitation Assessment Program (NAPAP)
tries to prevent acid rain corrosion of metals like iron and steel as well as marble, and limestone (286)
131
Readily absorbs water from the atmosphere and retains it. Ex. Sulfur trioxide colorless gas. From little droplets and then coalesce to produce larger droplets. Droplets form an aerosol with droplets about a micrometer in diameter. Does not absorb sunlight and can persist for several days
hygroscopic
132
Required hundreds of older power plants that emitted vast quantities of S)2, NOx and particulates to retrofit their operations with pollution controls
Regional Haze Rule (1999)
133
pH damaging lakes and streams
6. 5 = healthy pH
- below 6 fish and other aquatic life are affected
- 5 few species can survive
- 4 lake essentially a dead ecosystem
134
THe capacity of a lake or other body of water to resist a decrease in pH
acid-neutralizing capacity
limestone has a high acid neutralizing capacity b/c slowly reacts with acid rain (293)
granite - hard and not as reactive
