MSU CEM 141 FINAL EXAM Questions with
Detailed Verified Answers
scientific question Ans: can be answered by doing experiments, making observation,
taking measurements, etc. in a replicable way
Lights acts as what? Ans: Particle and wave.
scientific model Ans: drawing, graph, diagram, equation. represent many chemical
entities.
Wavelength Ans: The distance (m) of waves from peak to peak. Short: x-ray (red),
long: infrared (blue)
Short - higher energy
Long - lower energy
scientific theory Ans: 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) Ans: The number of wavefronts per second. Highest: x-ray
scientific law Ans: 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 Ans: C = 3.00 X 10^8
= wavelength X frequency
scientific explanation Ans: claim, evidence, reasoning
,Amplitude Ans: The intensity, height of peaks of waves. Highest: blue light
size of an atom Ans: 0.1 x 10^-9m
Energy of Wave (J) Ans: Increases as frequency increases and as wavelength decreases.
Highest: x-ray
Greek philosophers atomic theory Ans: -first atomic theory
-elements: earth, fire, water, air
-constantly in motion
-made of mostly empty space
Range of Wavelengths Ans: 10^-16 - 10^8 = 24. Only a third are visible
Black Body Radiation Ans: 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 ___ Ans: the observable properties
atom Ans: smallest distinguishable part of an element
Photoelectric Effect Ans: 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
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, how many atoms are naturally occurring? Ans: 91 naturally occurring elements
How many electrons are emitted if the light is below it's threshold frequency no
matter the intensity? Ans: None.
Dalton's atomic theory (1800s) Ans: -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?
Ans: Intensity.
JJ Thomson Ans: -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) Ans: Photon.
© Get it right 2025 Getaway - Stuvia US All rights reserved
Detailed Verified Answers
scientific question Ans: can be answered by doing experiments, making observation,
taking measurements, etc. in a replicable way
Lights acts as what? Ans: Particle and wave.
scientific model Ans: drawing, graph, diagram, equation. represent many chemical
entities.
Wavelength Ans: The distance (m) of waves from peak to peak. Short: x-ray (red),
long: infrared (blue)
Short - higher energy
Long - lower energy
scientific theory Ans: 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) Ans: The number of wavefronts per second. Highest: x-ray
scientific law Ans: 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 Ans: C = 3.00 X 10^8
= wavelength X frequency
scientific explanation Ans: claim, evidence, reasoning
,Amplitude Ans: The intensity, height of peaks of waves. Highest: blue light
size of an atom Ans: 0.1 x 10^-9m
Energy of Wave (J) Ans: Increases as frequency increases and as wavelength decreases.
Highest: x-ray
Greek philosophers atomic theory Ans: -first atomic theory
-elements: earth, fire, water, air
-constantly in motion
-made of mostly empty space
Range of Wavelengths Ans: 10^-16 - 10^8 = 24. Only a third are visible
Black Body Radiation Ans: 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 ___ Ans: the observable properties
atom Ans: smallest distinguishable part of an element
Photoelectric Effect Ans: 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
© Get it right 2025 Getaway - Stuvia US All rights reserved
, how many atoms are naturally occurring? Ans: 91 naturally occurring elements
How many electrons are emitted if the light is below it's threshold frequency no
matter the intensity? Ans: None.
Dalton's atomic theory (1800s) Ans: -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?
Ans: Intensity.
JJ Thomson Ans: -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) Ans: Photon.
© Get it right 2025 Getaway - Stuvia US All rights reserved
