Chem 101 Lab Final Exam 2025-2026
Questions with All Verified Answers.
When should you NOT wear gloves in the lab setting?
a. When weighing our 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 - Answer b and d
*also should not wear gloves when opening doors
General glove rules - 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
hand and onto your arm. Your wrist was exposed, and the solution came into direct contact with
your skin. What should you do? - Answer let your TA know and wash your skin under running
water for at least 15 minutes
When should goggles be worn in lab? - Answer The whole time you are in lab
You are taking an evening laboratory session and want to bring a snack to help you make it
though the evening. When should you be allowed to have food at the bench top in the lab?
a. If the experimental work is 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
the bench to prevent health issues. - Answer d. Never
, Precision - 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. -
Answer - a scale that is improperly calibrated and always reads 2.3 grams heavier than the
object actually 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
corrected for. It leads to unpredictable results. Results will likely cluster around true value.
Provide several examples. - Answer - wind speed might speed up or slow down at
unpredictable times
- any measurement between 2 markings because different people will read the measurement
differently
EXP 1: Why does ice float in water? - Answer Ice is less dense than water because the
negatively charged oxygen atoms repel one another due to Hydrogen bonding. After 4 C (40 F),
water begins losing density.
EXP 2: You measure NaOH by difference using an analytical balance. The initial mass of the
NaOH bottle is 5.042g. After removing the NaOH, the bottle mass is 4.812g. What is the mass of
the NaOH you are using? (use correct sig figs) - Answer 0.230 g
Mass is measured to _____ significant figs - Answer 4
Volume is measured to _____ significant figures - Answer 3
Density equation - Answer mass/volume
Find the density of liquid CO2. Remember that 1 mL=1 cm^3.
Mass - 55.05g, volume - 10mL - Answer 55.05g/10mL = 5.505 g/mL
Find the density of Dry Ice (solid CO2). Determine whether the solids will sink of float when put
into liquid CO2. Remember that 1 mL = 1 cm^3.
Questions with All Verified Answers.
When should you NOT wear gloves in the lab setting?
a. When weighing our 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 - Answer b and d
*also should not wear gloves when opening doors
General glove rules - 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
hand and onto your arm. Your wrist was exposed, and the solution came into direct contact with
your skin. What should you do? - Answer let your TA know and wash your skin under running
water for at least 15 minutes
When should goggles be worn in lab? - Answer The whole time you are in lab
You are taking an evening laboratory session and want to bring a snack to help you make it
though the evening. When should you be allowed to have food at the bench top in the lab?
a. If the experimental work is 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
the bench to prevent health issues. - Answer d. Never
, Precision - 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. -
Answer - a scale that is improperly calibrated and always reads 2.3 grams heavier than the
object actually 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
corrected for. It leads to unpredictable results. Results will likely cluster around true value.
Provide several examples. - Answer - wind speed might speed up or slow down at
unpredictable times
- any measurement between 2 markings because different people will read the measurement
differently
EXP 1: Why does ice float in water? - Answer Ice is less dense than water because the
negatively charged oxygen atoms repel one another due to Hydrogen bonding. After 4 C (40 F),
water begins losing density.
EXP 2: You measure NaOH by difference using an analytical balance. The initial mass of the
NaOH bottle is 5.042g. After removing the NaOH, the bottle mass is 4.812g. What is the mass of
the NaOH you are using? (use correct sig figs) - Answer 0.230 g
Mass is measured to _____ significant figs - Answer 4
Volume is measured to _____ significant figures - Answer 3
Density equation - Answer mass/volume
Find the density of liquid CO2. Remember that 1 mL=1 cm^3.
Mass - 55.05g, volume - 10mL - Answer 55.05g/10mL = 5.505 g/mL
Find the density of Dry Ice (solid CO2). Determine whether the solids will sink of float when put
into liquid CO2. Remember that 1 mL = 1 cm^3.
