Chapter 4 - Particulates and Gases Flashcards
Atomic Number
of protons in the nucleus
Atomic Mass
protons, neutrons, and electrons
measured in grams - average weight of the natural isotopes compared to carbon
Atomic weight of Sodium (Na)
23
Atomic weight of Hydrogen (H)
1
Atomic WEight of Carbon (C)
12
Atomic weight of Nitrogen (N)
14
Atomic Weight of Oxygen (O)
16
Atom
Basic unit of matter
Nucleus contains positively charged protons and neutrally charged nuetrons
Surrounded by a cloud of negatively charged electrons
Ion
Charged atom
Positively charged ions have fewer electrons than protons
Electron shell
Orbits of electrons around the nucleus
Number of electron shells determined by number of electrons
Valence Electrons
Electrons in the outermost electron shell
Shells with a complete number of electrons
Inert
Ionic Bonding
Two atoms exchange electrons
Covalent bonding
electrons are shared between two atoms in a molocule
usually non-metals
Moles
SI unit that describes the atomic weight in terms of grams/mole
Weight of one mole of a substance in grams is molar mass
1 mole has 6.02 x 10^23 atoms (Avagadro’s number)
Molecule
Unit of matter formed by the chemical combination of two or more atoms
Compound
Substance composed of all the same kinds of molecules (water)
Mixtures
Not the result of chemical bonding
consist of separate elements or compounds that are mixed together
solute
that which is dissolved
solvent
What a solute is dissolved into
Atomic Weight of a compound
Add atomic weights of individual atoms remembering to multiply the individual weights by the number of atoms of each present in the compound
pH
-log [H+]
Neutral pH
7
pH greater than 7
basic
pH below 7
acidic
Four gas laws
Boyle’s Law
Charles’ Law
Ideal Gas Law
Combined Gas Law
Boyle’s Law
P1V1=P2V2
At constant temperature, a fixed mass of gas occupies a volume, which is inversely proportional to the pressure exerted upon it
Charles’ Law
At constant temperature, the volume occupied by a fixed mass of gas is directly proportional to the absolute temperature
Volume1/ Temperature 1 = Volume 2/ Temperature 2
Ideal Gas Law
PV = nRT P= absolute pressure (psai) n= moles R = universal gas constant
Combined Gas Law
Combines Charles and Boyle’s Law
Pressure 1 * Volume 1 / Temp 1 = Pressure 2 * Volume 2 / Temp 2
Vapors
a gaseous form of a substance that is normally a solid or liquid at room temperature
Gases
substances that completely occupy a space and can be converted to a liquid or solid by increasing or decreasing temperature
Vapor Pressure
the pressure that a vapor at equilibrium with a pure liquid at a given temperature exerts to the surrounding atmosphere
Particulate
fine solid or liquid particles, such as dust, fog, mist, smoke, or spray
Dust
Solid particles generated by a mechanical action (crushing, grinding, etc.) Size ranges from 0.1 to 30um
Fume
Airborne solid particles formed by the condensation of vapor (ie welding fumes) Size ranges from 0.001 to 1.0um
Mist
`Suspended liquid droplets generated by condensation or atomization (fogs formed by condensation). Size ranges from 0.01 to 10um
Fibers
Particulate with an aspect ratios (length to width) of 3:1
Standard Temperature and Pressure
25C and 1 atm
In physical sciences STP = 0C and 1 atm
When discussing ventilation STP = 70F and 1 atm
Permissible Exposure Limit (PEL)
Maximum exposure concentration to a contaminant that an employee can be exposed to in an 8 hour workday
only OSHA standard that is enforceable by law
Threshold Limit Value (TLV)
Established by American Conference of Governmental Industrial Hygienist
Established exposure time for various contaminants in an 8 hour workday
AAGIH does not consider economic impact when establishing TLVs, so they are sometimes more strict than PELs
Time-weighted average (TWA)
Concentration that an employee is exposed to for a specific period of time
PEL and TLV both established for time weighted average of 8 hours
