CEM 141 Midterm Exam 2 Questions
Already Answered.
mole - Answer 6.022 x 10^23 things
number of particles that allows us to convert from the molecular to the macroscopic level
limiting reactant/reagent - Answer amount of one of the reactants which limits how much
product can be formed. smallest amount.
percent yield - Answer actual/theoretical x 100
electromagnetic radiation - Answer
wavelength - Answer The distance between two corresponding parts of a wave.
seconds/wave. 1/frequency. measured in m
amplitude - Answer Height of a wave
frequency - Answer waves/second. 1/wavelength. measured in Hz
Constant (c) - Answer 3 x 10^8 m/s. c=(wavelength)(frequency)
constructive interference - Answer The interference that occurs when two waves combine to
make a wave with a larger amplitude = brighter
destructive interference - Answer The interference that occurs when two waves combine to
make a wave with a smaller amplitude = darker
diffraction - Answer The bending of a wave as it moves around an obstacle or passes through a
narrow opening
models of light - Answer light as a wave/particle
, why is light considered a wave (evidence) - Answer diffraction, interference
why we consider light a wave (claim, evidence, reasoning) - Answer claim-light is a wave
evidence- diffraction, interference
reasoning- light acts the same as waves as demonstrated in diffraction and interference.
why is light considered a particle - Answer photoelectric effect. there is a threshold frequency
below which no electrons are emitted from metal when light is shined . if light were a wave, the
intensity should increase the energy and eject electrons.
photon - Answer Einstein postulated light must come in packets (particles or quanta)
energy - Answer E=hv
h=6.626x10^-34 J/s
visible spectrum - Answer light from the sun (white light) can be separated by a prism (first
done by Newton)
atomic emission spectrum - Answer light from one particular element does not contain all the
colors of the spectrum, only few wavelengths.
The discontinuous line spectra of light produced when excited atoms return to their ground
state and emit photons of a certain frequency.
atomic absorption spectrum - Answer The characteristic line spectrum that occurs as a result
of energy being absorbed by individual elements. Black lines on a continuum (coloured)
background.
spectra - Answer shows light at specific wavelength and energies
Bohr model of atom - Answer explained emission/absorption spectra by invoking discrete
energy levels characterized by quantum numbers (n). photons of e/m energy are emitted from
atoms as electrons move from one energy level to another. ONLY WORKS FOR HYDROGEN
atomic excitation - Answer excites orbital electron to higher energy level
Already Answered.
mole - Answer 6.022 x 10^23 things
number of particles that allows us to convert from the molecular to the macroscopic level
limiting reactant/reagent - Answer amount of one of the reactants which limits how much
product can be formed. smallest amount.
percent yield - Answer actual/theoretical x 100
electromagnetic radiation - Answer
wavelength - Answer The distance between two corresponding parts of a wave.
seconds/wave. 1/frequency. measured in m
amplitude - Answer Height of a wave
frequency - Answer waves/second. 1/wavelength. measured in Hz
Constant (c) - Answer 3 x 10^8 m/s. c=(wavelength)(frequency)
constructive interference - Answer The interference that occurs when two waves combine to
make a wave with a larger amplitude = brighter
destructive interference - Answer The interference that occurs when two waves combine to
make a wave with a smaller amplitude = darker
diffraction - Answer The bending of a wave as it moves around an obstacle or passes through a
narrow opening
models of light - Answer light as a wave/particle
, why is light considered a wave (evidence) - Answer diffraction, interference
why we consider light a wave (claim, evidence, reasoning) - Answer claim-light is a wave
evidence- diffraction, interference
reasoning- light acts the same as waves as demonstrated in diffraction and interference.
why is light considered a particle - Answer photoelectric effect. there is a threshold frequency
below which no electrons are emitted from metal when light is shined . if light were a wave, the
intensity should increase the energy and eject electrons.
photon - Answer Einstein postulated light must come in packets (particles or quanta)
energy - Answer E=hv
h=6.626x10^-34 J/s
visible spectrum - Answer light from the sun (white light) can be separated by a prism (first
done by Newton)
atomic emission spectrum - Answer light from one particular element does not contain all the
colors of the spectrum, only few wavelengths.
The discontinuous line spectra of light produced when excited atoms return to their ground
state and emit photons of a certain frequency.
atomic absorption spectrum - Answer The characteristic line spectrum that occurs as a result
of energy being absorbed by individual elements. Black lines on a continuum (coloured)
background.
spectra - Answer shows light at specific wavelength and energies
Bohr model of atom - Answer explained emission/absorption spectra by invoking discrete
energy levels characterized by quantum numbers (n). photons of e/m energy are emitted from
atoms as electrons move from one energy level to another. ONLY WORKS FOR HYDROGEN
atomic excitation - Answer excites orbital electron to higher energy level
