Chapter 1- The Air We Breathe
Catalyst
A chemical substance that particles in chemical reaction and influences its rate without itself undergoing permanent change
mixture
A physical combination of two or more pure substances present in variable amounts
matter and mass
In a chemical reaction, matter and mass are conserved
Parts per Million (PPM)
One ppm is a unit of concentration 10,000 times smaller than 1%
Violate
Readily passes into the vapor phase; that is, evaporated easily
scientific notation
a system of writing numbers as the product of a number and 10 raised to the appropriate power
organic compound
always contains carbon, almost always contains hydrogen, and may contain elements such as oxygen and nitrogen
carcinogenic
capable of causing cancer
Coalescents
chemicals added to soften the latex particles in paint so that these particles spread to form a continuous film of uniform thickness
metals
elements that are shiny and conduct electricity and heat well
nonmetals
elements that do not conduct heat or electricity well and have no one characteristic appearance
metalloids
elements that lie between metals and nonmetals on the periodic table and do not fail cleanly into either category
Aerosols
liquid and solid particles that remain suspended in the air rather that settling out
parts per billionth (ppb)
one part out of one billion, or 1000 times less concentrated than one part per million
chemical symbols
one- or two-letter abbreviations for the elements
periodic table an
orderly arrangement of all the element based on similarities in their properties
groups
organize elements according to important properties that they have in common and are numbered from left to right
percent
parts per hundred
Nanotechnology
refers to the creation of materials at the atomic and molecular (nanmoeters) scale: 1 nanometer (nm) = 1x10^-9m
chemical equation
representation of a chemical reaction using chemical formulas
exposure
the amount of substance encountered
troposphere
the lower region of the atmosphere in which we live that lies directly above the surface of the Earth
PMv10
Includes particles with an average diameter of 10um (micrometers 10^-6) or less, a length on the order of 0.0004 inches
hydrocarbons
compounds made up only of the elements hydrogen and carbon
ambient air
the air surrounding us, usually meaning the outside air
combustion
the chemical process of burnung; that is, the rapid combination of fuel with oxygen to release energy in the frm of heat and light
Respiration
the food we eat are metabolized to produce carbon dioxide and water
shifting baselines
the idea that what people expect as 'normal' on our planet has changed over time, especially with regard to ecosystems
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 probability of an outcome.
atoms
the smallest unit of an element that can exist as a stable, independent entity
molecule
two or more atoms held together by chemical bonds in a certain spatial arrangement
megacities
urban areas with 10 million people or more
tragedy of the commons
when a resource is common to all and used by many, but no one is particularly responsible for it. As a result, the resource may be destroyed by overuse to the detriment of all who use it.
green chemistry
'benign by design.' It calls for designing chemical products and processes that reduce or eliminate the use or generation of hazardous substances
secondary pollution
It is produced from chemical reactions involving one or more other pollutant
sustainability
The ability to keep in existence or maintain. A sustainable ecosystem is one that can be maintained. "Meeting the need of the present without compromising the ability of future generations to meet their needs"
PMv2.5
The subset of PMv10 and includes particles with an average diameter of less than 2.5 um (micrometers 10^-6)
significant figure
a digit that is included (or excluded) to correctly represent the accuracy with which an experimental quantity is known
microgram
a millionth of a gram (g) or 10^-6 g
diatomic
a molecule consisting of two atoms
chemical reaction
a process whereby substances described as reactants are transformed into different substances called products
compound
a pure substance made up of two or more different elements in a fixed, characteristic chemical combination
chemical formula
a symbolic way to represent elementary composition of a substance
violate organic compounds (VOCs)
carbon-containing compounds that pass easily into the vapor phase
element
one of the 100 or so pure substances in our world from which compounds are formed
noble gas
one of the inert elements in Group 8A taht undergoes few, if any, chemical reactions
halogens
one of the reactive nonmetals in Group 7A, such as flourine (F), Chlorine (Cl), bromine (Br), or iodine (I)