Cryoscopic Determination of Molecular Weight Post-Lab Questions (40 Points) Name Lab Instructor 1. A student performed a freezing point determination and calculated the molar mass of Lab Day Date an unknown like you did in this experiment. The only difference in procedure was that when determining the freezing point of the unknown-naphthalene mixture, they started with a clean empty test tube. If the following errors occurred, how would each affect the calculated molar mass of the solute (too high, too low, or no change)? Explain your answerS. A. The thermometer used actually read 2.0°C too low for all measurements The test tube was put flat on the lab bench and some naphthalene spilled out. The student did not reweigh the test tube, proceeded to determine both the freezing point of pure naphthalene and the freezing point of the unknown-naphthalene mixture. B. The student after weighing out 1.02 g of the unknown accidentally spilled a small amount onto the floor when pouring the unknown into the test tube containing the pure naphthalene. The test tube was not reweighed. C. After mixing the unknown with the naphthalene, the student put the test flat on the lab bench while getting a clamp from the lab drawer. After melting the mixture, the student realized some of the mixture had spilled onto the benchtop. D.

Question
Cryoscopic Determination of Molecular Weight
Post-Lab Questions (40 Points)
Name
Lab Instructor
1. A student performed a freezing point determination and calculated the molar mass of
Lab Day
Date
an unknown like you did in this experiment. The only difference in procedure was that
when determining the freezing point of the unknown-naphthalene mixture, they started with
a clean empty test tube. If the following errors occurred, how would each affect the
calculated molar mass of the solute (too high, too low, or no change)? Explain your
answerS.
A.
The thermometer used actually read 2.0°C too low for all measurements
The test tube was put flat on the lab bench and some naphthalene spilled out. The
student did not reweigh the test tube, proceeded to determine both the freezing
point of pure naphthalene and the freezing point of the unknown-naphthalene
mixture.
B.
The student after weighing out 1.02 g of the unknown accidentally spilled a small
amount onto the floor when pouring the unknown into the test tube containing the
pure naphthalene. The test tube was not reweighed.
C.
After mixing the unknown with the naphthalene, the student put the test flat on the
lab bench while getting a clamp from the lab drawer. After melting the mixture, the
student realized some of the mixture had spilled onto the benchtop.
D.
Expand
Transcribed Image Text

Cryoscopic Determination of Molecular Weight Post-Lab Questions (40 Points) Name Lab Instructor 1. A student performed a freezing point determination and calculated the molar mass of Lab Day Date an unknown like you did in this experiment. The only difference in procedure was that when determining the freezing point of the unknown-naphthalene mixture, they started with a clean empty test tube. If the following errors occurred, how would each affect the calculated molar mass of the solute (too high, too low, or no change)? Explain your answerS. A. The thermometer used actually read 2.0°C too low for all measurements The test tube was put flat on the lab bench and some naphthalene spilled out. The student did not reweigh the test tube, proceeded to determine both the freezing point of pure naphthalene and the freezing point of the unknown-naphthalene mixture. B. The student after weighing out 1.02 g of the unknown accidentally spilled a small amount onto the floor when pouring the unknown into the test tube containing the pure naphthalene. The test tube was not reweighed. C. After mixing the unknown with the naphthalene, the student put the test flat on the lab bench while getting a clamp from the lab drawer. After melting the mixture, the student realized some of the mixture had spilled onto the benchtop. D.

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