CEM 141 FINAL 2026 EXAM SCRIPT TEST PAPER
QUESTIONS AND SOLUTIONS GRADED A+
◉ scientific model.
Answer: drawing, graph, diagram, equation. represent many
chemical entities.
◉ Wavelength.
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.
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).
Answer: The number of wavefronts per second. Highest: x-ray
◉ scientific law.
,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.
Answer: C = 3.00 X 10^8
= wavelength X frequency
◉ scientific explanation.
Answer: claim, evidence, reasoning
◉ Amplitude.
Answer: The intensity, height of peaks of waves. Highest: blue light
◉ size of an atom.
Answer: 0.1 x 10^-9m
◉ Energy of Wave (J).
Answer: Increases as frequency increases and as wavelength
decreases. Highest: x-ray
◉ Greek philosophers atomic theory.
,Answer: -first atomic theory
-elements: earth, fire, water, air
-constantly in motion
-made of mostly empty space
◉ Range of Wavelengths.
Answer: 10^-16 - 10^8 = 24. Only a third are visible
◉ Black Body Radiation.
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 ___.
Answer: the observable properties
◉ atom.
Answer: smallest distinguishable part of an element
◉ Photoelectric Effect.
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?.
Answer: 91 naturally occurring elements
◉ How many electrons are emitted if the light is below it's threshold
frequency no matter the intensity?.
Answer: None.
◉ Dalton's atomic theory (1800s).
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?.
Answer: Intensity.
QUESTIONS AND SOLUTIONS GRADED A+
◉ scientific model.
Answer: drawing, graph, diagram, equation. represent many
chemical entities.
◉ Wavelength.
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.
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).
Answer: The number of wavefronts per second. Highest: x-ray
◉ scientific law.
,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.
Answer: C = 3.00 X 10^8
= wavelength X frequency
◉ scientific explanation.
Answer: claim, evidence, reasoning
◉ Amplitude.
Answer: The intensity, height of peaks of waves. Highest: blue light
◉ size of an atom.
Answer: 0.1 x 10^-9m
◉ Energy of Wave (J).
Answer: Increases as frequency increases and as wavelength
decreases. Highest: x-ray
◉ Greek philosophers atomic theory.
,Answer: -first atomic theory
-elements: earth, fire, water, air
-constantly in motion
-made of mostly empty space
◉ Range of Wavelengths.
Answer: 10^-16 - 10^8 = 24. Only a third are visible
◉ Black Body Radiation.
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 ___.
Answer: the observable properties
◉ atom.
Answer: smallest distinguishable part of an element
◉ Photoelectric Effect.
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?.
Answer: 91 naturally occurring elements
◉ How many electrons are emitted if the light is below it's threshold
frequency no matter the intensity?.
Answer: None.
◉ Dalton's atomic theory (1800s).
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?.
Answer: Intensity.
