Chemistry of the Environment Midterm

10^12

Tera (T)

10^9

Giga (G)

10^6

Mega (M)

10^3

Kilo (k)

10^-2

Centi (c)

10^-3

Milli (m)

10^-6

Micro (μ)

10^-9

Nano (n)

Atomic Number

Number of protons in an atom (6)

Atomic Mass

Number of protons and neutrons in an atom (12); the average mass of all the isotopes of an element

Allotropes

Different forms of the same element

Ore

A rock formation that contains a considerable amount of a desired element

Cradle-to-Cradle

The end of usefulness of one product dovetails with the beginning of the lifecycle for another product

Three Pillars of Sustainability

Environmental, Social, and Economic

78%

How much of the air is nitrogen

21%

How much of the air is oxygen

Troposphere

Lowest layer of earth's atmosphere (~0-15 km from ground); where pollution is found

Stratosphere

Second lowest layer of earth's atmosphere (~15- 50 km) from ground); home of the ozone layer (~15-30 km)

VOCs

Volatile Organic Compounds -goes easily into gas phase -acetone, gasoline

Carbon Monoxide

-toxic, odorless gas -primary source is exhaust from cars

Carbon Dioxide

-non-toxic, odorless gas -natural product of respiration and combustion

Nitrogen Dioxide

-characteristic brown color -visible component of urban smog -can combine with moist tissue in lungs to produce an acid -secondary pollutant

Secondary Pollutants

Pollutants that are formed by the combination of other pollutants in the atmosphere

Ozone

-has a sharp odor -can spoil many materials, such as plastics -affects lung function

Formation in the troposphere: NO2 -> NO + O (in sunlight) O + O2 -> O3

Sulfur Dioxide

-has a pungent odor -forms an acid in water -dissolves the moist tissue of your lungs to form an acid -formed when sulfur burns (coal-burning power stations)

Particulate Matter

Complex matter of tiny solid particles and microscopic liquid droplets

PM10

Particles with an average diameter of 10 micrometers (μm) or less

PM2.5

Particles with an average diameter of 2.5 micrometers (μm) or less

Pollutants from power plants

SO2, which ends up as H2SO4

Pollutants from Automobiles

CO and NOx

Combustion Reactions

Fuel + O2 -> CO2 + H2O

Incomplete Combustion

Not enough oxygen in a combustion reaction to form CO2

Green Chemistry

Reduces pollution through the design or redesign of chemical processes

Radiation

Energy emitted by a hot object and then absorbed by other objects; both wave-like and particle-like

Wavelength

λ; distance travelled between successive peaks (nm); inversely related to frequency

Frequency

ν; number of waves passing a fixed point in one second (s^-1 or Hz); inversely related to wavelength and directly related to energy

UVA

Wavelength is 320-400nm; lowest relative energy

UVB

Wavelength is 280-320nm; medium relative energy; breaks only O3 (single bonds)

UVC

Wavelength is 200-280nm; highest relative energy; breaks O2 and O3 (double bonds)

Covalent Bonding

Atoms achieve an inert gas structure by sharing electrons, rather than by gaining or losing; only between non-metals

Chapman Cycle

Net reaction is 3O2->2O3

CFCs

Chlorofluorocarbons (made up of C, F, and Cl)

Ionic Bonds

Electrons are transferred from a nonmetal to a metal (metal becomes a cation and nonmetal becomes an anion)

1 mol

6.02*10^23 atoms

1 mol C

12.01g C

Mass Percent

100*(total mass of atom)/(total mass of molecule)

UV Radiation

Causes molecule to dissociate

Infrared Radiation

Causes molecule to vibrate

Microwave Radiation

Causes molecule to rotate

Greenhouse Effect

Natural phenomenon in which IR radiation is trapped in the atmosphere

Greenhouse Gas

Any gas that is able to absorb IR radiation; most abundant is H2O; has to be a molecule containing at least three atoms connected to each other

Anthropogenic Gases

Human made gases that affect the climate; higher emissions of these greenhouse gases leads to higher average global temperatures

Weather

Short-term daily variations in temperature and conditions

Climate

Regional temperatures and conditions over decades; as CO2 emissions increase, so does average temperature of the earth

Cap-and-Trade System

Market-based pollution control system in which the government sets an overall limit on how much of a pollutant is acceptable and issues vouchers to pollute to each company, which companies are then free to trade

Water

-only substance that can exist as a solid, liquid, and gas at average Earth temperatures -expands on freezing, contracts on heating (from 0-4*C) -dissolves many substances -abnormally high boiling point and specific heat

Surface Water

Fresh water found in lakes, rivers, and streams

Aquifier

An underground permeable rock formation from which groundwater may be extracted using a well

Groundwater

Fresh water found in underground reservoirs also known as aquifers

Water Footprint

Estimate of the volume of fresh water used to produce a particular good or to provide a service

Solvent

A substance, often a liquid, capable of dissolving one or more pure substances

Solute

A substance that is dissolved in a solution

Aqueous Solution

A solution in which water is the solvent

Molarity

moles of solute/liters of solution

M=n/v

1 ppm

1mg/L

1 ppb

1μg/L

Electrolytes

Substances that will dissociate in water

Strong Electrolytes

Substances that completely dissociate into ions n water

Weak Electrolytes

Substances that only partially dissolve into ions in water

Precipatate

The solid deposited during a precipitation event, when a solid drops out of a homogeneous solution. This generally refers to an amorphous solid, with no long-range structural order, but it can also be used to describe a crystalline solid deposited slowly from a solution

Acid

Physical properties; sour taste, turns blue litmus paper red Chemical properties: can react with and dissolve marble, eggshell, or the shells of marine crustaceans Molecular level: releases H+ ions in aqueous solutions

Base

Physical properties: aqueous solutions have a slippery, soapy feel; turns red litmus paper blue, bitter taste Molecular level: produces OH- ions in aqueous solutions

Neutralization Reaction

Acid + Base -> water + salt

pH<7

H+>OH-

pH>7

H+<OH-

Coal

Main source of SO2 in the atmosphere

Ocean Acidification

Lowering of ocean pH due to increased atmospheric CO2

Carbonate Ion

CO3^2-; product of carbonic acid dissociating in ocean; reacts with H+ to form bicarbonate ion

Bicarbonate Ion

HCO3-; formed from reaction of carbonate ion with H+

Carbonic Acid

H2CO3; product of CO2 and H2O which dissociates into carbonate ion and H+

Distillation

A separation process in which a liquid solution is heated and the vapors are condensed and collected

Osmosis

Passage of water through a semipermeable membrane from a solution that is less concentrated to a solution that is more concentrated