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CHEM 121 EXAM 2 2025 ACTUAL EXAM QUESTIONS AND
CORRECT DETAILED ANSWERS|ALREADY GRADED A+
What is the energy (in J) of a mole of photons that have a wavelength of 701 nm? (h = 6.626 ×
10⁻³⁴ J • s and c = 3.00 × 10⁸ m/s) - ANSWER-1.70 × 10⁵ J
For which atomic orbital does n = 3 and ℓ = 1?
A) 2s
B) 3s
C) 3p
D) 3d
E) 4d - ANSWER-C
For the following electron configuration, identify the element and determine if it is in the
ground state or excited state. 1s²2s²2p⁶3s²3p⁶3d¹
A) K, ground state
B) K, excited state
C) Ca, ground state
D) Ca, excited state
E) Sc, ground state - ANSWER-B
Write the complete ground-state electron configuration of aluminum. - ANSWER-
1s²2s²2p⁶3s²3p¹
All of the orbitals in a given electron shell have the same value as the ________ quantum
number. - ANSWER-principal
A strong electrolyte is one that ______ completely in a solution - ANSWER-ionizes
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Line spectrum - ANSWER-a spectrum containing radiation of only specific wavelengths
continuous spectrum - ANSWER-the emission of a continuous range of frequencies of
electromagnetic radiation
visible spectrum - ANSWER-Light energy that can be seen and can be broken into the colors of
the rainbow.
It is impossible to know precisely what of an electron? - ANSWER-Position and the momentum
How many orbitals are there in the second shell - ANSWER-4 orbitals (8 electrons)
How many orbitals are in the third shell? - ANSWER-9
Enthalpy change for endothermic process is - ANSWER-Positive, meaning the system absorbs
heat from its surroundings
Enthalpy change for exothermic process - ANSWER-Negative because energy is always released
in the reaction
Give examples of endothermic reactions - ANSWER-melting, boiling, and evaporation in general
and photosynthesis
Give examples of exothermic reactions - ANSWER-Combustion, neutralisation, oxidation,
burning of a candle
Is dissolving an acid in water an endothermic or exothermic process - ANSWER-Exothermic
CHEM 121 EXAM 2 2025 ACTUAL EXAM QUESTIONS AND
CORRECT DETAILED ANSWERS|ALREADY GRADED A+
What is the energy (in J) of a mole of photons that have a wavelength of 701 nm? (h = 6.626 ×
10⁻³⁴ J • s and c = 3.00 × 10⁸ m/s) - ANSWER-1.70 × 10⁵ J
For which atomic orbital does n = 3 and ℓ = 1?
A) 2s
B) 3s
C) 3p
D) 3d
E) 4d - ANSWER-C
For the following electron configuration, identify the element and determine if it is in the
ground state or excited state. 1s²2s²2p⁶3s²3p⁶3d¹
A) K, ground state
B) K, excited state
C) Ca, ground state
D) Ca, excited state
E) Sc, ground state - ANSWER-B
Write the complete ground-state electron configuration of aluminum. - ANSWER-
1s²2s²2p⁶3s²3p¹
All of the orbitals in a given electron shell have the same value as the ________ quantum
number. - ANSWER-principal
A strong electrolyte is one that ______ completely in a solution - ANSWER-ionizes
, 2|Page
Line spectrum - ANSWER-a spectrum containing radiation of only specific wavelengths
continuous spectrum - ANSWER-the emission of a continuous range of frequencies of
electromagnetic radiation
visible spectrum - ANSWER-Light energy that can be seen and can be broken into the colors of
the rainbow.
It is impossible to know precisely what of an electron? - ANSWER-Position and the momentum
How many orbitals are there in the second shell - ANSWER-4 orbitals (8 electrons)
How many orbitals are in the third shell? - ANSWER-9
Enthalpy change for endothermic process is - ANSWER-Positive, meaning the system absorbs
heat from its surroundings
Enthalpy change for exothermic process - ANSWER-Negative because energy is always released
in the reaction
Give examples of endothermic reactions - ANSWER-melting, boiling, and evaporation in general
and photosynthesis
Give examples of exothermic reactions - ANSWER-Combustion, neutralisation, oxidation,
burning of a candle
Is dissolving an acid in water an endothermic or exothermic process - ANSWER-Exothermic
