CEM 141 - EXAM 2 QUESTIONS AND
ANSWERS WITH SOLUTIONS 2024
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
photoelectric effect - ANSWER The emission of electrons from a metal when light shines on the metal.
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
ANSWERS WITH SOLUTIONS 2024
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
photoelectric effect - ANSWER The emission of electrons from a metal when light shines on the metal.
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
