CHEM 101L FINAL QUESTIONS AND ANSWERS
Beer's law gives the mathematical relationship between solution concentration
and absorbance. According to Beer's law, the experimentally determined values
of absorbance (A) are given by multiplying: (Select all that apply)
A. ε, the molar extinction coefficient (also called molar absorptivity).
B. l, the path length of the cuvette.
Cterm-58hoice 3 of 4:C. c, the concentration of the solution.
Choice 4 of 4:D. t, the amount of time in the light beam.
According to the Safety Data Sheet (SDS) for iron(II) sulfate, what personal
protective equipment (PPE) are needed for safe handling? (Select all that apply.)
A) safety goggles
B)protective clothing
C) face shield
D) gloves
E) clean-room suit
F) respirator, if exposure limits are exceeded
A, B, C, D, F
What property of water is often used to initially evaluate purity of water samples?
A) volume
B)mass
C) density
D) temperature
C
What are the SI units for density?
A) kg/m^3
B) g/mL
C) g/cm^3
D) L/g
A
If the mass of your sample remains the same, but your volume increases, how
does this influence the density of the sample?
A) decrease
B) increase
C)stay the same
A
Consider each of the samples of water used in this experiment. Why should you
anticipate that these samples will have different densities?
A)They have differing amounts of contaminants.
B)They could have different temperatures.
C) The solutions are slightly different colors.
A
In this experiment, why is the mass of the buret segment with water measured
twice for each sample; once before and once after heating?
, A)The second measurement accounts for mass loss due to evaporation
B) The second measurement allows you to know if you have an accurate initial
measurement.
A
Why should the water in the buret segment be below the level of water in the 600
mL beaker?
A) To ensure that all of the water in the buret is heated consistently
B) So you can see the lines.
C) So that the contents of the buret segment does not spill over onto the lab
bench
A
What is the advantage of pooling your data with the rest of the lab section?
A) Reduces the effect of random error.
B) Reduces the effect of systematic error.
C) Lets you pick the data points that support your claim.
A
Do all laboratory instruments require calibration for proper use?
A) No
B) Yes
B
How many seconds can a flame be left unattended in this experiment?
A) it depends on the flammability of materials near the flame
B) ten seconds or less
C) as long as you're close by, there's no exact time
D) zero (it should never be left unattended)
D
Although goggles should always be worn in the lab, why are goggles an
especially important piece of protective equipment in this experiment?
A) to protect the eyes from heat coming from the Meker burner.
B) to keep any salt vapors from causing eyes to water.
C) to prevent eye damage from ultraviolet light produced by various light
sources.
C
How many decimal places beyond the markings of the instrument should one
estimate when taking a reading?
A) Zero
B) as many as needed such that the measurement always has two decimal places
C) One
D) it depends on the instrument
C
Which instruments will be used in this lab to record photoluminescence (i.e.,
emission of light)? (Select all that apply)
A) spectrometer with optical fiber
B) buret
C) spectroscope
D) colorimeter
Beer's law gives the mathematical relationship between solution concentration
and absorbance. According to Beer's law, the experimentally determined values
of absorbance (A) are given by multiplying: (Select all that apply)
A. ε, the molar extinction coefficient (also called molar absorptivity).
B. l, the path length of the cuvette.
Cterm-58hoice 3 of 4:C. c, the concentration of the solution.
Choice 4 of 4:D. t, the amount of time in the light beam.
According to the Safety Data Sheet (SDS) for iron(II) sulfate, what personal
protective equipment (PPE) are needed for safe handling? (Select all that apply.)
A) safety goggles
B)protective clothing
C) face shield
D) gloves
E) clean-room suit
F) respirator, if exposure limits are exceeded
A, B, C, D, F
What property of water is often used to initially evaluate purity of water samples?
A) volume
B)mass
C) density
D) temperature
C
What are the SI units for density?
A) kg/m^3
B) g/mL
C) g/cm^3
D) L/g
A
If the mass of your sample remains the same, but your volume increases, how
does this influence the density of the sample?
A) decrease
B) increase
C)stay the same
A
Consider each of the samples of water used in this experiment. Why should you
anticipate that these samples will have different densities?
A)They have differing amounts of contaminants.
B)They could have different temperatures.
C) The solutions are slightly different colors.
A
In this experiment, why is the mass of the buret segment with water measured
twice for each sample; once before and once after heating?
, A)The second measurement accounts for mass loss due to evaporation
B) The second measurement allows you to know if you have an accurate initial
measurement.
A
Why should the water in the buret segment be below the level of water in the 600
mL beaker?
A) To ensure that all of the water in the buret is heated consistently
B) So you can see the lines.
C) So that the contents of the buret segment does not spill over onto the lab
bench
A
What is the advantage of pooling your data with the rest of the lab section?
A) Reduces the effect of random error.
B) Reduces the effect of systematic error.
C) Lets you pick the data points that support your claim.
A
Do all laboratory instruments require calibration for proper use?
A) No
B) Yes
B
How many seconds can a flame be left unattended in this experiment?
A) it depends on the flammability of materials near the flame
B) ten seconds or less
C) as long as you're close by, there's no exact time
D) zero (it should never be left unattended)
D
Although goggles should always be worn in the lab, why are goggles an
especially important piece of protective equipment in this experiment?
A) to protect the eyes from heat coming from the Meker burner.
B) to keep any salt vapors from causing eyes to water.
C) to prevent eye damage from ultraviolet light produced by various light
sources.
C
How many decimal places beyond the markings of the instrument should one
estimate when taking a reading?
A) Zero
B) as many as needed such that the measurement always has two decimal places
C) One
D) it depends on the instrument
C
Which instruments will be used in this lab to record photoluminescence (i.e.,
emission of light)? (Select all that apply)
A) spectrometer with optical fiber
B) buret
C) spectroscope
D) colorimeter
