MSU CEM 141 FINAL EXAM
QUESTIONS AND ANSWERS
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)
-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? - -Intensity.
- JJ Thomson - --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) - -Photon.
- 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
, - Energy of light equation? - -E = hV.
- plum pudding model - --atoms contained electrons embedded in the
middle
-JJ Thomson
- h - -Planck's constant, the energy of a photon.
- alpha particle - -2 neutrons, 2 protons
- What happens to the energy when there is a short wavelength? - -High
energy.
- Light from the sun (white light) can be separated by a prism to create this,
only a small part of the full EM spectrum? - -Visible Spectrum.
- Rutherford - --gold foil experiment
-atoms mostly empty space
-small, dense, positively charged nucleus
- Gold foil experiment - --most particles went straight through
-every once in awhile particles were deflected
-1/8000 particles bounced back
-led to model of atom; small, dense, positively charged nucleus
- Atomic Emission Spectrum - -Spectrum that emits photons, energy
diagram: electron goes down energy levels.
- neutrons - --discovered in 1932
-slightly heavier than protons
- Atomic Absorption Spectrum - -Spectrum that absorbs photons, energy
diagram: electrons goes up in energy levels.
- Current model of atom - --nucleus contains protons and neutrons
-cloud of electrons
- Heisenberg Uncertainty Principle - -Principle states that we can't
accurately measure both the position and the energy of a small particle
(electron)
Bohr's model did - why its wrong.
- charges of electrons, protons, neutrons - --electrons: -1, 1/3000 amu
-protons: +1, 1 amu
-neutrons: 0 charge, 1 amu
QUESTIONS AND ANSWERS
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)
-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? - -Intensity.
- JJ Thomson - --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) - -Photon.
- 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
, - Energy of light equation? - -E = hV.
- plum pudding model - --atoms contained electrons embedded in the
middle
-JJ Thomson
- h - -Planck's constant, the energy of a photon.
- alpha particle - -2 neutrons, 2 protons
- What happens to the energy when there is a short wavelength? - -High
energy.
- Light from the sun (white light) can be separated by a prism to create this,
only a small part of the full EM spectrum? - -Visible Spectrum.
- Rutherford - --gold foil experiment
-atoms mostly empty space
-small, dense, positively charged nucleus
- Gold foil experiment - --most particles went straight through
-every once in awhile particles were deflected
-1/8000 particles bounced back
-led to model of atom; small, dense, positively charged nucleus
- Atomic Emission Spectrum - -Spectrum that emits photons, energy
diagram: electron goes down energy levels.
- neutrons - --discovered in 1932
-slightly heavier than protons
- Atomic Absorption Spectrum - -Spectrum that absorbs photons, energy
diagram: electrons goes up in energy levels.
- Current model of atom - --nucleus contains protons and neutrons
-cloud of electrons
- Heisenberg Uncertainty Principle - -Principle states that we can't
accurately measure both the position and the energy of a small particle
(electron)
Bohr's model did - why its wrong.
- charges of electrons, protons, neutrons - --electrons: -1, 1/3000 amu
-protons: +1, 1 amu
-neutrons: 0 charge, 1 amu
