CHEM 102L Final Exam Review
Questions And Answers
When should you not wear gloves in the laboratory setting? (select all that apply)
a. When weighing out reagents at the balances
b. When entering data into your ELN on your laptop
c. When adding a Kimwipe to the solid waste container
d. When handling clean glassware
e. When opening the door to go to the restroom
f. When writing notes on scratch paper using a pen and paper
g. When adding chemicals to the liquid waste
b, e, f
You are adding 0.1 M NaOH to a cuvette containing crystal violet. While using the
micropipette, you spill 100µL onto your bare arm. What should you do?
wash off w/ water, tell TA
Iron Man is taking an evening laboratory session and wants to bring a snack to
help him make to through the evening. When should he be allowed to have food
at the bench top in the lab?
a. If the experiment work is over and cleaned up
b. At the beginning because it is dinner time and crime fighting is exhausting
c. Only if the food remains in the students backpack while at the bench top
d. Never
e. Iron Man is hypoglycemic and should be allowed to eat at the bench to prevent
health issues
d
______ error arises from a flaw in the equipment or in the experimental design.
This type of error ____ be detected and corrected. Provide several examples.
, systematic, can
sig figs, old equipment, incorrect calibration
______ error arises from uncontrolled, and often times uncontrollable, variables
in an experiment which has equal chance of being positive and negative. This
type of error ____ be detected and corrected. Provide several examples.
random, can't
inaccurate reading of buret (miniscus), equipment noise (movement)
Define accuracy
how close a measurement is to the true value
What does systematic error affect more: accuracy or precision? How does one
minimize the influence of systematic error in one's results?
accuracy
- calibrate correctly
- read/use equipment correctly
Define precision
how close the measured values are to each other
What does random error effect more: accuracy or precision? How does one
minimize the influence of random error in one's results?
precision
- use more modern equipment
Accuracy or precision?
You determined the molar mass of unknown fatty acid #3 dissolved into stearic
acid to be 219.4 g/mol. Unknown fatty acid #3 was myristic acid which has a
molar mass of 228.37 g/mol. What was your percent error to the correct number
of significant figures?
a. 3.9%
b. 3.93%
c. 4.1%
d. 4.08%
b
(|219.4 - 228.37| / 228.37) x 100
Questions And Answers
When should you not wear gloves in the laboratory setting? (select all that apply)
a. When weighing out reagents at the balances
b. When entering data into your ELN on your laptop
c. When adding a Kimwipe to the solid waste container
d. When handling clean glassware
e. When opening the door to go to the restroom
f. When writing notes on scratch paper using a pen and paper
g. When adding chemicals to the liquid waste
b, e, f
You are adding 0.1 M NaOH to a cuvette containing crystal violet. While using the
micropipette, you spill 100µL onto your bare arm. What should you do?
wash off w/ water, tell TA
Iron Man is taking an evening laboratory session and wants to bring a snack to
help him make to through the evening. When should he be allowed to have food
at the bench top in the lab?
a. If the experiment work is over and cleaned up
b. At the beginning because it is dinner time and crime fighting is exhausting
c. Only if the food remains in the students backpack while at the bench top
d. Never
e. Iron Man is hypoglycemic and should be allowed to eat at the bench to prevent
health issues
d
______ error arises from a flaw in the equipment or in the experimental design.
This type of error ____ be detected and corrected. Provide several examples.
, systematic, can
sig figs, old equipment, incorrect calibration
______ error arises from uncontrolled, and often times uncontrollable, variables
in an experiment which has equal chance of being positive and negative. This
type of error ____ be detected and corrected. Provide several examples.
random, can't
inaccurate reading of buret (miniscus), equipment noise (movement)
Define accuracy
how close a measurement is to the true value
What does systematic error affect more: accuracy or precision? How does one
minimize the influence of systematic error in one's results?
accuracy
- calibrate correctly
- read/use equipment correctly
Define precision
how close the measured values are to each other
What does random error effect more: accuracy or precision? How does one
minimize the influence of random error in one's results?
precision
- use more modern equipment
Accuracy or precision?
You determined the molar mass of unknown fatty acid #3 dissolved into stearic
acid to be 219.4 g/mol. Unknown fatty acid #3 was myristic acid which has a
molar mass of 228.37 g/mol. What was your percent error to the correct number
of significant figures?
a. 3.9%
b. 3.93%
c. 4.1%
d. 4.08%
b
(|219.4 - 228.37| / 228.37) x 100
