Exam 2 Flashcards
(98 cards)
Frequency
V
Wavelength
λ
Frequency measured in
hertz
Wavelength measured in
nm
Speed of light (on formula sheet)
C
3.00 * 108 m/s (
Energy and Frequency
Directly proportional
Energy and Wavelength
Inversely proportional
Wavelength and Frequency
Inversely Proportional
Energy of a photon equations (2 equations)
E= h * v (on formula sheet)
E= h*c/λ
E=J/Photon
What is h?
Planck’s constant
6.26*10-34J/s
(on formula sheet)
convert m to nm
convert m to um
1m= 1*109nm
1m=1*106um
ROYGBIV
Red low energy, longest wavelength. (infrared next to red)
Violet is highest energy, shortest wavelength. (UV next to violet)
ROYGBIV
Energy ——>
Frequency ——>
<————wavelength
Remember: Wavelength is inversely proportional!
Avagadros for light problems!
1 mol of photons/6.022*10^23 photons
Take something like #KJ/mol. Convert KJ to J then multiply by 1mol/6.022*1023photons so you get J/photon that can be used in E equations. E=hc/λ
Or if you have number of J/photon and want it in moles, multiply by 6.022*1023photons/1mole.
E=hc/λ
λ should be what unit?
METERS
q=mc∆T
c=4.184 J/gC heat capacity of water
m is mass in grams
Electron moving to a different energy level
only if it absorbs or emits a photon that has the same energy as the difference between the two energy levels
ground state
lowest energy oribtal n=1 for hydrogen
Excited State
When the electron is at a higher energy orbital n=2+ for hydrogen
Ionize
When an electron is ejected from an atom. Nfinal=infinity.
Losing an electron.
Exothermic and endothermic electrons
Electrons go from a high level (7) to a low level (2). ∆H= neg. Emission!
Endothermic go from low (2) to a high level (7). Absorption!
Lyman series
UV 90-100nm
ends at n=1
Balmer Series
400 to 700
Ends at n=2
Visible Light
IR series
IR 1000 nms
ends at n=3
all the series are exothermic BTW. High to low level.
Rydberg Equation Wavelength of electron transition in a Hydrogen atom
(all given on formula sheet)
1/λ =R(1/n12-n22)
n2>n1!!
R=1.097*107
