MSU CEM 141 FINAL EXAM QUESTIONS & ANSWERS
1. scientific question: can be answered by doing experiments, making observation, taking measurements,
etc. in a replicable way
2. Lights acts as what?: Particle and wave.
3. scientific model: drawing, graph, diagram, equation. represent many chemical entities.
4. Wavelength: The distance (m) of waves from peak to peak. Short: x-ray (red), long: infrared (blue)
Short - higher energy
Long - lower energy
5. 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
6. Frequency (V): The number of wavefronts per second. Highest: x-ray
7. 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)
8. Velocity of Light: C = 3.00 X 10^8
= wavelength X frequency
9. scientific explanation: claim, evidence, reasoning
10. Amplitude: The intensity, height of peaks of waves. Highest: blue light
11. size of an atom: 0.1 x 10^-9m
12. Energy of Wave ( J): Increases as frequency increases and as wavelength decreases. Highest: x-ray
13. Greek philosophers atomic theory: -first atomic theory
-elements: earth, fire, water, air
-constantly in motion
-made of mostly empty space
14. Range of Wavelengths: 10^-16 - 10^8 = 24. Only a third are visible
,15. 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
16. molecular structure of a substance determines : the observable properties
17. atom: smallest distinguishable part of an element
,18. 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
19. how many atoms are naturally occurring?: 91 naturally occurring elements
20. How many electrons are emitted if the light is below it's threshold frequency
no matter the intensity?: None.
21. Dalton's atomic theory (1800s): -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
22. What increases the number of electrons to be emitted by the photoelectric
effect?: Intensity.
23. JJ Thomson: -first person to provide evidence of electron
-cathode ray tube
-plum pudding model
-particles carried electric charge
24. A particle that transfers light energy with a definable energy, emits
one electron
energy of = h (6.626 x 10^-34 J): Photon.
25. cathode ray tube: -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
26. Energy of light equation?: E = hV.
1. scientific question: can be answered by doing experiments, making observation, taking measurements,
etc. in a replicable way
2. Lights acts as what?: Particle and wave.
3. scientific model: drawing, graph, diagram, equation. represent many chemical entities.
4. Wavelength: The distance (m) of waves from peak to peak. Short: x-ray (red), long: infrared (blue)
Short - higher energy
Long - lower energy
5. 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
6. Frequency (V): The number of wavefronts per second. Highest: x-ray
7. 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)
8. Velocity of Light: C = 3.00 X 10^8
= wavelength X frequency
9. scientific explanation: claim, evidence, reasoning
10. Amplitude: The intensity, height of peaks of waves. Highest: blue light
11. size of an atom: 0.1 x 10^-9m
12. Energy of Wave ( J): Increases as frequency increases and as wavelength decreases. Highest: x-ray
13. Greek philosophers atomic theory: -first atomic theory
-elements: earth, fire, water, air
-constantly in motion
-made of mostly empty space
14. Range of Wavelengths: 10^-16 - 10^8 = 24. Only a third are visible
,15. 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
16. molecular structure of a substance determines : the observable properties
17. atom: smallest distinguishable part of an element
,18. 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
19. how many atoms are naturally occurring?: 91 naturally occurring elements
20. How many electrons are emitted if the light is below it's threshold frequency
no matter the intensity?: None.
21. Dalton's atomic theory (1800s): -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
22. What increases the number of electrons to be emitted by the photoelectric
effect?: Intensity.
23. JJ Thomson: -first person to provide evidence of electron
-cathode ray tube
-plum pudding model
-particles carried electric charge
24. A particle that transfers light energy with a definable energy, emits
one electron
energy of = h (6.626 x 10^-34 J): Photon.
25. cathode ray tube: -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
26. Energy of light equation?: E = hV.
