CHEM 102L FINAL EXAM REVIEW
2026 ACTUAL QUESTIONS WITH
VERIFIED ANSWERS.
*Experiment 0: Safety in the Lab and General Error*
Why do you take three absorbance measurements of the same
solution while rotating the cuvette 180° between each
measurement? - correct answer-
In Experiment 15: Chemical Equilibria, the experimental
purpose for creating a Beer's Law plot for [Fe(NCS)]²⁺ is best
described as:
a. To demonstrate the linear relationship between the
concentration of [Fe(NCS)]²⁺ and absorbance
b. To determine the concentration of [Fe(NCterm-67S)]²⁺ in a
solution at equilibrium
c. To determine the initial concentration of [Fe(NCS)]²⁺ in a
solution before equilibrium is achieved
d. To follow the progress fo the reaction of Fe³⁺ and NCS⁻ -
correct answer-a
,In Experiment 15: Chemical Equilibria, you used Le Chatelier's
principle when preparing your solutions for the standard curve
(Beer's Law plot).
What is Le Chatelier's principle? - correct answer-when there's
a change in the system, it will change to meet equilibrim
The equilibrium below was the reaction of interest in
Experiment 15. In the preparation of your standard solutions,
which reactant was used in excess? Which reactant was
essentially converted entirely to product?
Fe³⁺+SCN⁻↔[Fe(NCS)]²⁺ - correct answer-Fe is used in excess
and SCN was forced to completion (product).
True or False. The Keq changes as the initial concentrations of
Fe³⁺ and SCN⁻ change. - correct answer-true
True or False. At equilibrium, the concentrations of the
reactant(s) and product(s) are constant. - correct answer-true
, True or False. Equilibrium is a static process and no reactions
occur once equilibrium is achieved. - correct answer-false
In Experiment 15: Chemical Equilibria, what were the standard
and equilibrium solutions used for, respectively? - correct
answer-standard --> used to form equilibrium solution
equilibrium --> used to find concentration of Fe(NCS)2+
What is the definition of λmax? How was it used in this
experiment? - correct answer-wavelength where absorbance is
max; to determine the concentration at that wavelength
What is the keq? - correct answer-C^c x D^d / A^a x B^b
When calibrating the spectrometer, you accidently blanked on a
slightly colored solution that had an absorbance of 0.1 at the
λmax. This means that every absorbance measured for the
standard curve will be 0.1 lower than what the value should be.
How will this influence your standard curve relative to a
spectrometer that was calibrated correctly?
a. The slope of the standard curve will be unchanged, but the y-
intercept will be -0.1
2026 ACTUAL QUESTIONS WITH
VERIFIED ANSWERS.
*Experiment 0: Safety in the Lab and General Error*
Why do you take three absorbance measurements of the same
solution while rotating the cuvette 180° between each
measurement? - correct answer-
In Experiment 15: Chemical Equilibria, the experimental
purpose for creating a Beer's Law plot for [Fe(NCS)]²⁺ is best
described as:
a. To demonstrate the linear relationship between the
concentration of [Fe(NCS)]²⁺ and absorbance
b. To determine the concentration of [Fe(NCterm-67S)]²⁺ in a
solution at equilibrium
c. To determine the initial concentration of [Fe(NCS)]²⁺ in a
solution before equilibrium is achieved
d. To follow the progress fo the reaction of Fe³⁺ and NCS⁻ -
correct answer-a
,In Experiment 15: Chemical Equilibria, you used Le Chatelier's
principle when preparing your solutions for the standard curve
(Beer's Law plot).
What is Le Chatelier's principle? - correct answer-when there's
a change in the system, it will change to meet equilibrim
The equilibrium below was the reaction of interest in
Experiment 15. In the preparation of your standard solutions,
which reactant was used in excess? Which reactant was
essentially converted entirely to product?
Fe³⁺+SCN⁻↔[Fe(NCS)]²⁺ - correct answer-Fe is used in excess
and SCN was forced to completion (product).
True or False. The Keq changes as the initial concentrations of
Fe³⁺ and SCN⁻ change. - correct answer-true
True or False. At equilibrium, the concentrations of the
reactant(s) and product(s) are constant. - correct answer-true
, True or False. Equilibrium is a static process and no reactions
occur once equilibrium is achieved. - correct answer-false
In Experiment 15: Chemical Equilibria, what were the standard
and equilibrium solutions used for, respectively? - correct
answer-standard --> used to form equilibrium solution
equilibrium --> used to find concentration of Fe(NCS)2+
What is the definition of λmax? How was it used in this
experiment? - correct answer-wavelength where absorbance is
max; to determine the concentration at that wavelength
What is the keq? - correct answer-C^c x D^d / A^a x B^b
When calibrating the spectrometer, you accidently blanked on a
slightly colored solution that had an absorbance of 0.1 at the
λmax. This means that every absorbance measured for the
standard curve will be 0.1 lower than what the value should be.
How will this influence your standard curve relative to a
spectrometer that was calibrated correctly?
a. The slope of the standard curve will be unchanged, but the y-
intercept will be -0.1
