CEM 141
MSU CEM 141 FINAL EXAM QUESTIONS AND
ANSWERS GRADED A+ 2026
scientific question -Correct Answer ✔-can be answered by doing experiments,
making observation, taking measurements, etc. in a replicable way
Lights acts as what? -Correct Answer ✔-Particle and wave.
scientific model -Correct Answer ✔-drawing, graph, diagram, equation. represent
many chemical entities.
Wavelength -Correct Answer ✔-The distance (m) of waves from peak to peak.
Short: x-ray (red), long: infrared (blue)
Short - higher energy
Long - lower energy
scientific theory -Correct Answer ✔-A well tested concept that explains a wide
range of observations (explains why). changes with time. Explains the underlying
cause of a range of phenomena
Frequency (V) -Correct Answer ✔-The number of wavefronts per second. Highest:
x-ray
scientific law -Correct Answer ✔-A theory that has been tested by and is
consistent with generations of data. a rule that describes a pattern in nature
(explains what)
Velocity of Light -Correct Answer ✔-C = 3.00 X 10^8
= wavelength X frequency
scientific explanation -Correct Answer ✔-claim, evidence, reasoning
CEM 141
,CEM 141
Amplitude -Correct Answer ✔-The intensity, height of peaks of waves. Highest:
blue light
size of an atom -Correct Answer ✔-0.1 x 10^-9m
Energy of Wave (J) -Correct Answer ✔-Increases as frequency increases and as
wavelength decreases. Highest: x-ray
Greek philosophers atomic theory -Correct Answer ✔--first atomic theory
-elements: earth, fire, water, air
-constantly in motion
-made of mostly empty space
Range of Wavelengths -Correct Answer ✔-10^-16 - 10^8 = 24. Only a third are
visible
Black Body Radiation -Correct Answer ✔-When a mass is heated it emits a type of
EM radiation, at very high temps the mass becomes "white hot" because all
wavelengths of visible light become equally intense
molecular structure of a substance determines ___ -Correct Answer ✔-the
observable properties
atom -Correct Answer ✔-smallest distinguishable part of an element
Photoelectric Effect -Correct Answer ✔-Metals emit electrons when
electromagnetic radiation shines on the surface, light is transfers energy to the
electrons at the metal's surface where it's transformed into KE that gives the
electrons enough energy to leave the atom
Depends on frequency not intensity
how many atoms are naturally occurring? -Correct Answer ✔-91 naturally
occurring elements
CEM 141
, CEM 141
How many electrons are emitted if the light is below it's threshold frequency no
matter the intensity? -Correct Answer ✔-None.
Dalton's atomic theory (1800s) -Correct Answer ✔--elements composed of small,
indivisible, indestructible, particles (atoms)
-all atoms of each element are identical (mass/properties)
-no subatomic particles
-compounds are formed by combos of atoms from 2+ elements
-chemical reactions occur from rearrangement of atoms
What increases the number of electrons to be emitted by the photoelectric
effect? -Correct Answer ✔-Intensity.
JJ Thomson -Correct Answer ✔--first person to provide evidence of electron
-cathode ray tube
-plum pudding model
-particles carried electric charge
A particle that transfers light energy with a definable energy, emits one electron
energy of = h (6.626 x 10^-34 J) -Correct Answer ✔-Photon.
cathode ray tube -Correct Answer ✔--JJ Thomson
-electron particles were emitted from cathodes
-particles carried electric charge
-ray was independent of the element it came from
-particles identical regardless of cathode
-proved all atoms contained electrons
Energy of light equation? -Correct Answer ✔-E = hV.
plum pudding model -Correct Answer ✔--atoms contained electrons embedded in
the middle
-JJ Thomson
CEM 141
MSU CEM 141 FINAL EXAM QUESTIONS AND
ANSWERS GRADED A+ 2026
scientific question -Correct Answer ✔-can be answered by doing experiments,
making observation, taking measurements, etc. in a replicable way
Lights acts as what? -Correct Answer ✔-Particle and wave.
scientific model -Correct Answer ✔-drawing, graph, diagram, equation. represent
many chemical entities.
Wavelength -Correct Answer ✔-The distance (m) of waves from peak to peak.
Short: x-ray (red), long: infrared (blue)
Short - higher energy
Long - lower energy
scientific theory -Correct Answer ✔-A well tested concept that explains a wide
range of observations (explains why). changes with time. Explains the underlying
cause of a range of phenomena
Frequency (V) -Correct Answer ✔-The number of wavefronts per second. Highest:
x-ray
scientific law -Correct Answer ✔-A theory that has been tested by and is
consistent with generations of data. a rule that describes a pattern in nature
(explains what)
Velocity of Light -Correct Answer ✔-C = 3.00 X 10^8
= wavelength X frequency
scientific explanation -Correct Answer ✔-claim, evidence, reasoning
CEM 141
,CEM 141
Amplitude -Correct Answer ✔-The intensity, height of peaks of waves. Highest:
blue light
size of an atom -Correct Answer ✔-0.1 x 10^-9m
Energy of Wave (J) -Correct Answer ✔-Increases as frequency increases and as
wavelength decreases. Highest: x-ray
Greek philosophers atomic theory -Correct Answer ✔--first atomic theory
-elements: earth, fire, water, air
-constantly in motion
-made of mostly empty space
Range of Wavelengths -Correct Answer ✔-10^-16 - 10^8 = 24. Only a third are
visible
Black Body Radiation -Correct Answer ✔-When a mass is heated it emits a type of
EM radiation, at very high temps the mass becomes "white hot" because all
wavelengths of visible light become equally intense
molecular structure of a substance determines ___ -Correct Answer ✔-the
observable properties
atom -Correct Answer ✔-smallest distinguishable part of an element
Photoelectric Effect -Correct Answer ✔-Metals emit electrons when
electromagnetic radiation shines on the surface, light is transfers energy to the
electrons at the metal's surface where it's transformed into KE that gives the
electrons enough energy to leave the atom
Depends on frequency not intensity
how many atoms are naturally occurring? -Correct Answer ✔-91 naturally
occurring elements
CEM 141
, CEM 141
How many electrons are emitted if the light is below it's threshold frequency no
matter the intensity? -Correct Answer ✔-None.
Dalton's atomic theory (1800s) -Correct Answer ✔--elements composed of small,
indivisible, indestructible, particles (atoms)
-all atoms of each element are identical (mass/properties)
-no subatomic particles
-compounds are formed by combos of atoms from 2+ elements
-chemical reactions occur from rearrangement of atoms
What increases the number of electrons to be emitted by the photoelectric
effect? -Correct Answer ✔-Intensity.
JJ Thomson -Correct Answer ✔--first person to provide evidence of electron
-cathode ray tube
-plum pudding model
-particles carried electric charge
A particle that transfers light energy with a definable energy, emits one electron
energy of = h (6.626 x 10^-34 J) -Correct Answer ✔-Photon.
cathode ray tube -Correct Answer ✔--JJ Thomson
-electron particles were emitted from cathodes
-particles carried electric charge
-ray was independent of the element it came from
-particles identical regardless of cathode
-proved all atoms contained electrons
Energy of light equation? -Correct Answer ✔-E = hV.
plum pudding model -Correct Answer ✔--atoms contained electrons embedded in
the middle
-JJ Thomson
CEM 141
