CHEM 115

Winter 2000

Ch 2: List of Important Concepts, Values (1/5/00)

Conversions:

km = 1.6 miles

T(^oC) = 5/9(T(^oF) - 32)

kg = 2.2 lbs.

inch = 2.54 cm

T(K) = T(^oC) + 273

Prefixes:

nano

micro

milli

centi

deci

kilo

mega

giga

10^x x =

-9

-6

-3

-2

+2

+3

+6

+9

Avagadro's number Na = 6.02 x10⁺²³

Planck's constant = 6.62 x10^-34 J s

Speed of light c = 3.00 x10⁺⁸m/s

1 atm = 1 bar = 1000 mbar

Gas constant R = 8.21 x 10^-2 (atm L/(mole K) STP = (1 atm, O ^oC)

Mole of carbon = 12.0 grams C = Avagadro's nunber (N_a ) of carbon atoms

Density = mass/volume

Number density = molecules/volume

Mixing ratio = mole fraction = relative concentration (ppm, ppb, ppt, etc)

Ideal Gas Law: PV=nRT

(P= pressure, V= volume, n = number moles, T in K)

Dalton's Law of Partial Pressures:

total gas pressure = sum of partial pressures of the individual components of the gas mixture

Absorption and Emission of Light (EM Radiation): E = hn

Excited state

ground state

photolysis

heat of reaction D H_o

Speed of light (c) equals wavelength (l ) times the frequency (n ): c = l n

Reaction mechanism

catalyst

free-radical

rate constant (k)

Steady state (production rate = loss rate, so concentration is constant)

Chapman cycle of ozone production and loss

Dobson unit (DU)

Stratosphere

troposphere

temperature inversion

UVA UVB UVC