CHEM 102L FINAL EXAM REVIEW
EXAM QUESTIONS AND ANSWERS 100%
PASS
*Experiment 0: Safety in the Lab and General Error* -
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 - ANS 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? - ANS 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
@COPYRIGHT ALL RIGHTS RESERVED PAGE 1 OF 16
,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
- ANS 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. - ANS 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. - ANS random, can't
inaccurate reading of buret (miniscus), equipment noise (movement)
Define accuracy - ANS 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? - ANS accuracy
- calibrate correctly
- read/use equipment correctly
Define precision - ANS 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? - ANS precision
- use more modern equipment
Accuracy or precision? - ANS
@COPYRIGHT ALL RIGHTS RESERVED PAGE 2 OF 16
, 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% - ANS b
(|219.4 - 228.37| / 228.37) x 100
Describe how to use a micropipette. - ANS When using the micropitpette, depress the
plunger to the first stop when drawing in the liquid and to the second stop when dispensing the
liquid.
Describe how to use a volumetric flask. - ANS - only room temp
- use burette funnel
- make sure all sides are coated with solution
- no stir bar
Describe how to use a burette. - ANS read top to bottom 1 is top then 2 then 3 as go down
*Experiment 11: Gas Laws* - ANS
For the graph on the right, ______ is the dependent variable and ______ is the independent
variable. - ANS Pressure, Inverse Temp
x-axis is independent variable, y-axis is dependent variable
The graphs above indicate that the mathematical relationship between the variables and of
pressure and temperature is ____________. - ANS directly proportional
--> the pressure increases as temp increases
@COPYRIGHT ALL RIGHTS RESERVED PAGE 3 OF 16
EXAM QUESTIONS AND ANSWERS 100%
PASS
*Experiment 0: Safety in the Lab and General Error* -
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 - ANS 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? - ANS 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
@COPYRIGHT ALL RIGHTS RESERVED PAGE 1 OF 16
,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
- ANS 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. - ANS 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. - ANS random, can't
inaccurate reading of buret (miniscus), equipment noise (movement)
Define accuracy - ANS 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? - ANS accuracy
- calibrate correctly
- read/use equipment correctly
Define precision - ANS 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? - ANS precision
- use more modern equipment
Accuracy or precision? - ANS
@COPYRIGHT ALL RIGHTS RESERVED PAGE 2 OF 16
, 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% - ANS b
(|219.4 - 228.37| / 228.37) x 100
Describe how to use a micropipette. - ANS When using the micropitpette, depress the
plunger to the first stop when drawing in the liquid and to the second stop when dispensing the
liquid.
Describe how to use a volumetric flask. - ANS - only room temp
- use burette funnel
- make sure all sides are coated with solution
- no stir bar
Describe how to use a burette. - ANS read top to bottom 1 is top then 2 then 3 as go down
*Experiment 11: Gas Laws* - ANS
For the graph on the right, ______ is the dependent variable and ______ is the independent
variable. - ANS Pressure, Inverse Temp
x-axis is independent variable, y-axis is dependent variable
The graphs above indicate that the mathematical relationship between the variables and of
pressure and temperature is ____________. - ANS directly proportional
--> the pressure increases as temp increases
@COPYRIGHT ALL RIGHTS RESERVED PAGE 3 OF 16
