CHEM 101 LAB FINAL EXAM QUESTIONS
WITH CORRECT ANSWERS
When should you NOT wear gloves in the lab setting?
a. When weighingBour reagents at the balances
b. When entering in data on your laptop
c. When handling clean glassware
d. When writing notes on scratch paper using a pen and paper - CORRECT ANSWER -b and d
*also should not wear gloves when opening doors
General glove rules - CORRECT ANSWER -- you should never reuse gloves
- dispose of gloves if they are heavily contaminated
- dispose of gloves if they are torn
- dispose of gloves in the glove hazardous waste container
- gloves must be worn at all times while handling chemicals or glassware
- do not wear gloves outside of lab
You make a solution of 0.1M NaOH and accidentally spill the solution, covering your gloved han
d and onto your arm. Your wrist was exposed, and the solution came into direct contact with yo
ur skin. What should you do? - CORRECT ANSWER -
let your TA know and wash your skin under running water for at least 15 minutes
When should goggles be worn in lab? - CORRECT ANSWER -The whole time you are in lab
You are taking an evening laboratory session and want to bring a snackBto help you make it thou
gh the evening. When should you be allowed to have food at the bench top in the lab?
a. If the experimental workBis over and cleaned up
, b. At the beginning because it is dinner time and being a student is exhausting.
c. Only if the food remains in the students backpack while at the bench top.
d. Never.
e. Never, unless you have a tendency to become hypoglycemic, then you are allowed to eat at t
he bench to preventBhealth issues. - CORRECT ANSWER -d. Never
Accuracy - CORRECT ANSWER -
A measure of how close a measurement is to the true value of the quantity measured.
Precision - CORRECT ANSWER -
A measure of how close a series of measurements are to one another.
Systematic error arises from a flaw in the equipment or in the experimental design. This type of
error can be detected and corrected. It leads to predictable results. Provide several examples. -
CORRECT ANSWER --
a scale that is improperly calibrated and always reads 2.3 grams heavier than the object actuall
y is
- a stretched out measuring tape that always reads values lower than the true value.
Random error arises from uncontrolled, often uncontrollable, variables in an experiment which
has equal chance of being positive and negative. This type of error cannot be detected or correc
ted for. It leads to unpredictable results. Results will likely cluster around true value. Provide sev
eral examples. - CORRECT ANSWER --
wind speed might speed up or slow down at unpredictable times
-
any measurement between 2 markings because different people will read the measurement dif
ferently
EXP 1: Why does ice float in water? - CORRECT ANSWER -
Ice is less dense than water because the negatively charged oxygen atoms repel one another du
e to Hydrogen bonding. After 4 C (40 F), water begins losing density.
WITH CORRECT ANSWERS
When should you NOT wear gloves in the lab setting?
a. When weighingBour reagents at the balances
b. When entering in data on your laptop
c. When handling clean glassware
d. When writing notes on scratch paper using a pen and paper - CORRECT ANSWER -b and d
*also should not wear gloves when opening doors
General glove rules - CORRECT ANSWER -- you should never reuse gloves
- dispose of gloves if they are heavily contaminated
- dispose of gloves if they are torn
- dispose of gloves in the glove hazardous waste container
- gloves must be worn at all times while handling chemicals or glassware
- do not wear gloves outside of lab
You make a solution of 0.1M NaOH and accidentally spill the solution, covering your gloved han
d and onto your arm. Your wrist was exposed, and the solution came into direct contact with yo
ur skin. What should you do? - CORRECT ANSWER -
let your TA know and wash your skin under running water for at least 15 minutes
When should goggles be worn in lab? - CORRECT ANSWER -The whole time you are in lab
You are taking an evening laboratory session and want to bring a snackBto help you make it thou
gh the evening. When should you be allowed to have food at the bench top in the lab?
a. If the experimental workBis over and cleaned up
, b. At the beginning because it is dinner time and being a student is exhausting.
c. Only if the food remains in the students backpack while at the bench top.
d. Never.
e. Never, unless you have a tendency to become hypoglycemic, then you are allowed to eat at t
he bench to preventBhealth issues. - CORRECT ANSWER -d. Never
Accuracy - CORRECT ANSWER -
A measure of how close a measurement is to the true value of the quantity measured.
Precision - CORRECT ANSWER -
A measure of how close a series of measurements are to one another.
Systematic error arises from a flaw in the equipment or in the experimental design. This type of
error can be detected and corrected. It leads to predictable results. Provide several examples. -
CORRECT ANSWER --
a scale that is improperly calibrated and always reads 2.3 grams heavier than the object actuall
y is
- a stretched out measuring tape that always reads values lower than the true value.
Random error arises from uncontrolled, often uncontrollable, variables in an experiment which
has equal chance of being positive and negative. This type of error cannot be detected or correc
ted for. It leads to unpredictable results. Results will likely cluster around true value. Provide sev
eral examples. - CORRECT ANSWER --
wind speed might speed up or slow down at unpredictable times
-
any measurement between 2 markings because different people will read the measurement dif
ferently
EXP 1: Why does ice float in water? - CORRECT ANSWER -
Ice is less dense than water because the negatively charged oxygen atoms repel one another du
e to Hydrogen bonding. After 4 C (40 F), water begins losing density.
