Chemistry in Context Chapter 1
Why does paint contain VOCs
*Because paint has antifreeze additives so the paint does not freeze in winter and keeps paint from drying out. *Because paint has coalescents to soften latex particles in paint *Because paints contain oils that that react with oxygen and produce VOCs overtime
What do we expect more of indoors?
*Carbon monoxide because it is relatively unreactive *some VOCs
Nitrogen monoxide and nitrogen dioxide emissions
*Collectively known as NOx *NO2 is brown in color giving smog its brownish tint *N2 and O2 produce NO which is a colorless gas but.. * NO reacts with Ozone to form NO2 and Oxygen *NOx connects to the breakdown of VOCs in the air *Limited success in curbing NOx emissions which in turn means limited success in curbing ozone
How does precipitin affect air pollution?
*"scrubbing the air" -will decrease the concentration of pollutants (cleans out air)
How many elements occur naturally on Earth?
About 90 elements occur naturally. The others have been created from existing elements through nuclear reactions
What is air?
Air is a mixture that contains different molecules
Periodic table
An orderly arrangement of all the elements based on similarities in their properties created by 19th century russian chemist Dmitri Mendeleev
Why are toxicities difficult to assess?
Because it is unethical to run these experiments on people
Why is there high levels of oxygen in the atmosphere?
Because of alga, plants and trees that produce oxygen through photosyntheis
What two elements are liquids?
Bromine and Mercury are liquids at room temperature
What are the health effects of carbon monoxide?
Carbon monoxide poisoning *carbon monoxide has a strong affinity to hemoglobin and binds very tightly with it preventing CO2 and O2 from binding with hemoglobin *hemoglobin is responsible for binding with CO2 and O2 to carry oxygen to tissues so they can perform cellular respiration *because of carbon monoxide, blood cells don't exchange CO2 and O2 and one can experience nausea, heart attack, coma or death
What pollutants do tailpipes puff out?
Carbon monoxide, volatile organic compounds, nitrogen oxides, and particulate matter
Water vapor and carbon dioxide are what?
Compounds
why have carbon monoxide emissions decreased?
Improved engine design, computerized sensors that better adjust fuel-oxygen mixture, and most importantly, the requirement that all cars manufactured since the 1970s have catalytic converters
chemical symbols
One or two letter abbreviations for the elements
Which pollutant under the National Ambient air Quality standards is likely to be the most toxic?
Ozone (O3)
What does lightning produce?
Ozone and nitrogen oxides
How does ozone levels vary?
Ozone levels vary with weather, season and latitude because sunlight is involved in ozone formation
What is considered the most harmful air pollutant?
PM2.5 *Because it causes many respiratory diseases
What can certain particulate matter get passed?
PM50 gets into nose PM10 gets into throat PM2.5 gets into lungs and enters blood stream
What do wildfires produce?
Particulate matter and carbon monoxide
What is the best known human-made element?
Plutonium *fuel both nuclear reactions and nuclear bombs
Volatile Organic Compounds
Pollutants that are not regulated but are still intimately connected with the ones that are
What are the health effects of ozone?
Potent lung irritant *lungs become inflamed and tissues are "stressed out" *exacerbates asthma
What do catalytic converters do?
Reduce the amount of carbon monoxide in the exhaust stream by catalyzing the combustion of CO and CO2. They also lower NOx emissions by catalyzing the conversions of nitrogen oxides back to N2 and O2
What is another indoor pollutant?
Rhadon *Usually no problem but it may reach hazardous levels in basements, mines and caves
what does ozone attack?
Rubber and damages tires
The Clean Air Act of 1970
Set national air quality standards
The vast majority of elements are what?
Solids
What do volcanoes release?
Sulfur dioxide
What are the health effects of sulfur oxides?
Sulfur oxide is a bronchiaconstrictor! *asthma inducing
What does cigarette smoke do?
carbon monoxide and Co2
Volatile Organic Compounds
carbon-containing compounds that pass easily into vapor phase
coalescents
chemicals added to soften the latex particles in paint
hydrocarbons
compounds made up only of elements hydrogen and carbon
What can a candle do to air quality?
deplete oxygen levels in a room and produce soot, carbon monoxide, and VOCs
In the troposphere, elements nitrogen and oxygen exist as what?
diatomic molecules
PM2.5
fine particles *These particles, when inhaled, go deep into your lungs and can pass from your lungs into your bloodstream and can cause heart disease
sick building syndrome
indoor pollutants reach hazardous levels
noble gas
inert elements that undergo few chemical reactions EX = Argon
parts per billion
meaning one part out of one billion, or 1000 times less concentrated than parts per million *ppm to ppb move decimal three places to the right
diatomic molecule
molecule consisting of two atoms
How does lead enter air today?
mostly as dust
How many compounds have been identified?
over 20 million
What does NOx produce?
photochemical smog
Pollutants in the environments are often expressed as...
ppm
Chemical reaction
process whereby substances described as reactants are transformed into different substances, called products
Secondary pollutant
produced from chemical reactions involving one or more other pollutants
volatile substance
readily passes into the vapor phase and evaporates easily EX. Gasoline and nail polish remover
What are the health effects of NOx
respiratory inflammation
Chemical formula
symbolic way to represent the elementary composition of a substance
tragedy of the commons
term used by Garret Hardin who said tragedy occurs when a resource is common to all and used by many, but has no one in particular responsible. As a result, resource is depleted. The costs are shared by all
Ambient Air
the air surrounding us
exposure
the amount of the substance encountered
Combustion
the chemical process of burning, that is, the rapid reaction of fuel with oxygen to release energy in the form of heat and light
Nanotechnology
the creation of materials at the atomic and molecular scale (nanometer)
toxicity
the intrinsic health hazard of a substance
risk assessment
the process of evaluating scientific data and making predictions in an organized manner about the probabilities of an outcome
chemical equation
the representation of a chemical reaction using chemical formulas Reactants --> Products
atom
the smallest particle of a substance
Air pollution
the waste we stash in our atmosphere
NAAQS air pollutants are monitored because..
they are threats to our health
Cars not only emit carbon in the form of CO but also in the form of...
unburned and partially burned hydrocarbons. (VOCs)
megacities
urban areas with 10 million people or more
VOCs from tailpipes are...
vapors of incompletely burned gasoline molecules or fragments of these molecules. *The exhaust gas still contains oxygen, as not all of it is consumed in the engine. Catalytic converters will utilize this oxygen to burn VOCs to form carbon dioxide and water *VOCs aid in the formation of nitrogen dioxide
groups
vertical columns
From what is sulfur oxides released?
volcanic eruptions and burning of coal
What is another source of carbon monoxide?
wildfires! They contribute 10% each year
What percent of air is in the troposphere?
75%
What does every compound exhibit?
A constant characteristic chemical composition
Do we escape pollutants indoors?
If a pollutant is highly reactive, it does not persist long enough to make it indoors.
Air pollution can be
both natural and man-made
carcinogenic
capable of causing cancer
Molecules in a single drop of water contain how many atoms?
5X10^21 atoms
1 nanometer = how many meters?
1X10^-9 m
Sulfur dioxide emissions
*Linked to the coal that is burned to generate electric power *Although coal consists mostly of carbon, it may contain 1-3% sulfur together with small amounts of minerals. The sulfur burns to form sulfur dioxide and the minerals end up as fine ash particles. SO2 and and ash go right out the smokestack *this SO2 produced by burning coal can dissolve in the water droplets of clouds and fall to the ground as acid rain *Once in the air, SO2 can react with oxygen to form sulfur trioxide! If the air is humid enough, they help condense water vapor into an aerosol of tiny water droplets. This sulfuric acid aerosol is small enough to become trapped in the lung tissue and cause severe damage GOOD NEWS = sulfur dioxide emissions in the U.S are declining (accredited to the clean air act 1970) *small amounts of sulfur were found in gasoline and diesel fuel but these amounts were lowered in 1993 and 2006
How is ozone produced?
*Ozone is a secondary pollutant *product of the reaction between VOCs and NO2 *the energy provided by sunlight splits one of the bonds in NO2 molecule which returns to NO and O. This oxygen atoms produced then can react with oxygen molecules to produce ozone *Sunlight is needed to split NO2 so ozone levels go down at night
Particulate matter
*PM10 and PM2.5 * Many different sources: -wildfires in the summer, wood stoves in the winter, construction sites, mining, and even unpaved roads. **They can form in atmosphere too *tough pollutant to control
Carbon monoxide emissions
*Primarily from automobiles *Dramatic reduction of carbon monoxide has occurred despite more cars on the street (decreased almost 60% since 1980)
What are the health effects of gasoline?
*damage brain and nervous system *slowed growth and development *learning and behavior problems as well as hearing and speech impermetn
typical composition of inhaled and exhaled air
-Nitrogen inhaled 78% and exhaled 78% -Oxygen inhaled 21% and exhaled 16% -Argon inhaled .9% and exhaled .9% -Carbon Dioxide inhaled .04% and exhaled 4%
What is the atmosphere made of?
1) 78% Nitrogen 2) 21% Oxygen 3) .9% Argon 4) .03% Carbon Dioxide And small percentages of other elements
Which pollutants are monitored under the National Ambient Air Quality Standards
1) Carbon Monoxide 2) Nitrogen Dioxide 3) Ozone 4) Particulate 5) Sulfur Dioxide
What factors does exposure depend on?
1) Concentration in air *the more toxic the pollutant, the lower its concentration must be set 2) Length of time 3) Rate of breathing
what are the two types of smog?
1) Industrial smog (directly emitted) 2) photochemical smog(secondary pollutant) - formed by chemical reaction wit sun
Classification of MAtter
1) MAtter A. Mixtures B. Pure Substances -Elements -Compounds
what are two major sources of air pollutants?
1) Motor Vehicles 2) Coal-fired plants that generate electricity
What do these two sources directly emit?
1) SO2 (sulfur dioxide) 2) CO (carbon monoxide) 3) NO (Nitrogen Oxide) 4) PM (Particulate matter)
What may change in chemical equations?
1) The number or molecules in reactants may differ from the number in products 2) Physical states (solid, liquid, gas)
What are the risks presented by an air pollutant a function of?
1) Toxicity 2) Exposure
What are some natural sources of air pollution?
1) Volcanic eruptions 2) Lightening reactions 3) Wild fires 4) Pollen
How is carbon dioxide produced?
1) humans exhale Carbon dioxide (CO2) with each breath. Breathing is one natural source 2) Also produced when humans burn fuels (through combustion)
Four pure substances that make up the majority of the atmosphere
1)Nitrogen 2)Oxygen 3)Argon 4)Water Vapor
Pollutants found at very low concentrations
1)Ozone 2)Sulfur dioxide 3)Carbon monoxide 4)Nitrogen dioxide
What are some human sources of air pollution?
1)automobiles 2)combustion of fuels 3)deforestation 4)agriculture 5
What are the criteria pollutants?
1)carbon monoxide 2)nitrogen oxide 3)sulfur oxide 4)particulate matter 5)ozone 6)Lead
What factors are considered in determining AQI forecast?
1)sunlight / cloud cover 2) Emissions activities (traffic) 3) Precipitation 4)wind patterns
What are the hydrocarbons we used today obtained from?
Crude oils EX. Methane - simplest hydrocarbon and primary component of natural gas
Have the concentrations of air pollutants in the U.S increased or decreased?
Decreased
Why do some locations have good air and some have bad?
Differences arise because of the number of people living in a region, their activities, the geographical features . the prevailing weather patterns and the activities of people in neighboring regions
What does matter consist of?
Elements and compounds
How come there are so many compounds yet only 100 elements?
Elements have the ability to combine in many different ways
Metal elements
Elements that are shiny and conduct electricity and heat well. The majority of the elements are metals *Iron, gold, copper
Nonmetal elements
Elements that do not conduct heat or electricity well and have no one characteristic appearance. (Hydrogen and the right side of periodic table) *Hydrogen, sulfure, chlorine and oxygen
Metaloids
Elements that lie between metals and nonmetals on the periodic table and do not fall cleanly into either category. *ALso called semimetals and include semiconductors silicon and germanium
The Pollution Prevention Act of 1990
Focused on preventing the formation of hazardous substances, stating that "pollution should be prevented and reduced at the source whenever feasible"
Tiny amounts of what is in the air?
Helium, xenon, and Radon
What does sulfur oxides form?
Industrial smog and formation of particulate matter EX. Great smog in London 1952 - high levels of sulfur dioxide
How does wind patterns effect air pollution?
Jet stream can act like tail pipe and flow pollution out
How come lead levels have drastically decreased?
Lead was once an additive in gasoline to lower emissions but was collectively harming people (especially children) *It is no longer in gasoline
U.S Clean Air Act of 1970
Led to the establishment of air quality standards *focused on limiting our exposure to hazardous substances
In what areas do people sometimes still breathe unhealthy air?
Metropolitan areas EX. Los Angeles
Does NO or NO2 come out of tailpipe?
NO comes directly out of tailpipe or smokestack. But overtime in the presence of VOCs and OH, NO is converted to NO2 in the atmosphere
Do vehicles emit sulfur dioxide?
NO. Because cars have eternal combustion engines primarily fueled by gasoline which produces carbon dioxide and water vapor
what molecules do we expect less of indoors?
O3, NO2, and SO2
Air inversions
Occur when the cooler air gets trapped beneath warmer air. Air pollutants can accumulate in an inversion layer, especially if the layer remains stationary for an extended period. *Occurs in cities rimmed by mountains EX. Salt Lake City
When and where is ozone more likely?
On long summer days especially in congested urban areas
Element
One of the 100 or so pure substances in our world from which compounds are formed. THEY CONTAIN ONLY ONE TYPE OF ATOM EX. Nitrogen / oxygen
Air Quality Index
The Index is scaled from 1-500 *Green or yellow (less than or equal to 100) means indicates air of good or moderate quality *Orange indicates unhealthy for some groups(100-150) *Red,purple or maroon indicates that air is unhealthy for everyone (greater than 150)
Who established the National Ambient Air Quality Standards?
The U.S Environmental Protection Agency
Explain the depth of the troposphere?
The depth of the troposphere varies with season and location. Its depth ranges from about 12 miles (20km) at the equator to about 4 miles(6km) at the poles
Law of conservation of matter and mass
The elements do not change their identities when converted from reactant to product, although, they are bonded in different ways *MAtter and mass are conserved *The mass of the reactants consumed equals the mss of the products formed
troposphere
The lower region of the atmosphere in which we live that lies directly above the surface of the earth *tropos = greek for turning *air currents and turbulent atoms that turn and mix our air
How do ozone concentrations vary during the day?
The ozone levels drop in the absence of sunlight, after sundown
Where does the warm and cold air lie in the troposphere?
The warmest air usually lies at ground level because the sun primarily heats the ground, which in turn warms the air above it. Cooler air is found higher up.
Complete combustion
There is enough oxygen present that hydrocarbons burn completely. CO2 is formed
Incomplete combustion
There is not enough oxygen present for hydrocarbon to burn completely. Only carbon monoxide is formed, not carbon dioxide
How do atoms change in a chemical reaction?
They are neither created nor destroyed
Argon and helium exist as what?
Uncombined atoms
Where are the majority of people living?
Urban areas
Sustainability
Using resources in a manner so that future generations can have the same quality of life
When and where does temperate inversion take place?
Usually in evenings in the summer and in warmer climates
What does paint contain?
VOCs *important to use nontoxic paints!
Where does particulate matter source from?
Vehicle engines, coal burning power plants, wildfires, and blowing dust *Sometimes visible as soot or smoke
How does warm and cold air act?
Warm air rises and gets cooler and warmer air has higher pressure. Cold air sinks
Ozone in the atmosphere
We want ozone in the stratosphere but not in the troposphere
Explain combustion
When the carbon containing compounds burn, the carbon combines with oxygen to produce carbon dioxide. When the oxygen supply is limited, carbon monoxide is likely to form as well
catalyst
a chemical substance that participates in a chemical reaction and influences its rate without itself undergoing permanent change *catalytic converters typically use metals such as platinum and rhodium as catalysts
mixture
a physical combination of two or more pure substances present in variable amounts
Compound
a pure substance made up of two or more different elements in a fixed, characteristic chemical combination. CONTAIN TWO OR MORE DIFFERENT TYPES OF ATOMS EX. H2O Water is a compound of the two elements oxygen and hydrogen
Green chemistry
a set of key ideas to guide all in the chemistry community *"benign by design" * calls for designing chemical products and processes that reduce or eliminate the use or generation of hazardous substances *Use less energy, create less waste, use fewer resources, and use renewable resources
scientific notation
a system for writing numbers as the product of a number and 10 raised to the appropriate power *count zeroes and add that number to exponent of 10 * EX. 10,000 = 1X10^4
Inversion layer
air pollutants accumulate into a layer because cold air is trapped under warm air
what do Organic compounds contain?
always contains carbon, almost always contains hydrogen, and may contain other elements such as oxygen and nitrogen
molecule
atoms held together by chemical bonds
