MSU CEM 141 FINAL EXAM 2026-2027 KEY
TERMS QUESTIONS AND ANSWERS GRADED A+
scientific question
can be answered by doing experiments, making observation, taking measurements,
etc. in a replicable way
Lights acts as what?
Particle and wave.
scientific model
drawing, graph, diagram, equation. represent many chemical entities.
Wavelength
The distance (m) of waves from peak to peak. Short: x-ray (red), long: infrared
(blue)
Short - higher energy
Long - lower energy
scientific theory
,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)
The number of wavefronts per second. Highest: x-ray
scientific law
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
C = 3.00 X 10^8
= wavelength X frequency
scientific explanation
claim, evidence, reasoning
Amplitude
The intensity, height of peaks of waves. Highest: blue light
,size of an atom
0.1 x 10^-9m
Energy of Wave (J)
Increases as frequency increases and as wavelength decreases. Highest: x-ray
Greek philosophers atomic theory
-first atomic theory
-elements: earth, fire, water, air
-constantly in motion
-made of mostly empty space
Range of Wavelengths
10^-16 - 10^8 = 24. Only a third are visible
Black Body Radiation
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 ___
, the observable properties
atom
smallest distinguishable part of an element
Photoelectric Effect
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?
91 naturally occurring elements
How many electrons are emitted if the light is below it's threshold frequency no
matter the intensity?
None.
Dalton's atomic theory (1800s)
-elements composed of small, indivisible, indestructible, particles (atoms)
-all atoms of each element are identical (mass/properties)
TERMS QUESTIONS AND ANSWERS GRADED A+
scientific question
can be answered by doing experiments, making observation, taking measurements,
etc. in a replicable way
Lights acts as what?
Particle and wave.
scientific model
drawing, graph, diagram, equation. represent many chemical entities.
Wavelength
The distance (m) of waves from peak to peak. Short: x-ray (red), long: infrared
(blue)
Short - higher energy
Long - lower energy
scientific theory
,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)
The number of wavefronts per second. Highest: x-ray
scientific law
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
C = 3.00 X 10^8
= wavelength X frequency
scientific explanation
claim, evidence, reasoning
Amplitude
The intensity, height of peaks of waves. Highest: blue light
,size of an atom
0.1 x 10^-9m
Energy of Wave (J)
Increases as frequency increases and as wavelength decreases. Highest: x-ray
Greek philosophers atomic theory
-first atomic theory
-elements: earth, fire, water, air
-constantly in motion
-made of mostly empty space
Range of Wavelengths
10^-16 - 10^8 = 24. Only a third are visible
Black Body Radiation
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 ___
, the observable properties
atom
smallest distinguishable part of an element
Photoelectric Effect
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?
91 naturally occurring elements
How many electrons are emitted if the light is below it's threshold frequency no
matter the intensity?
None.
Dalton's atomic theory (1800s)
-elements composed of small, indivisible, indestructible, particles (atoms)
-all atoms of each element are identical (mass/properties)
