CHEM 121 LAB FINAL EXAM QUESTIONS WITH ALL
POSSIBLE SOLUTIONS ANSWERED 2024/2025
When using the Tare function on a balance, start by (1). Then (2) to cancel out
that mass. Finally, (3) and record the mass of your sample.
1) Placing the glassware on the balance
2) Press the Tare/Zero button
3) Add your sample to the glassware
5.43 g
A balance with ±0.01 g tolerance
1.230 g
A balance with ±0.001 g tolerance
4.0000 g
A balance with ±0.0001 g tolerance
A graduated cylinder contains 10.00 mL water. A 14.74 g piece of aluminum is
added to the water, and the volume rises to 15.46 mL. What is the density of the
aluminum in g/mL?
density = mass/volume
d = 14.74g / 5.46mL = 2.70 mL
A 24.5 g sample of solution has a density of 0.768 g/mL. What is the sample
volume (in mL)?
, 31.9 mL
v = mass/density
v = 31.9 mL
In order to use a pipet, place a (1) at the top of the pipet. Use this object to fill the
pipet such that the (2) of the liquid is even with the volume line. Release the
liquid, touching the tip of the pipet to the side of the container if necessary to
release the last drop (3) the pipet tip.
1) Bulb or pump
2) Meniscus
3) Outside
Identify effective techniques for accurate pipet use.
1) Do not let liquid enter the pipet bulb or pump.
2) Measure liquid by aligning the meniscus with the volume line.
Accuracy
The closeness between a measurement and its accepted value.
Precision
The closeness among a set of measurements.
A series of measurements in the lab led to an experimental result of 32.9 mL, with
a calculated standard deviation of 0.3 mL. What is the standard way to report this
result?
32.9 ± 0.3 mL
A cube of plastic 1.3 × 10−5 km on a side has a mass of 2.1 g. What is its density
in g/cm3?
POSSIBLE SOLUTIONS ANSWERED 2024/2025
When using the Tare function on a balance, start by (1). Then (2) to cancel out
that mass. Finally, (3) and record the mass of your sample.
1) Placing the glassware on the balance
2) Press the Tare/Zero button
3) Add your sample to the glassware
5.43 g
A balance with ±0.01 g tolerance
1.230 g
A balance with ±0.001 g tolerance
4.0000 g
A balance with ±0.0001 g tolerance
A graduated cylinder contains 10.00 mL water. A 14.74 g piece of aluminum is
added to the water, and the volume rises to 15.46 mL. What is the density of the
aluminum in g/mL?
density = mass/volume
d = 14.74g / 5.46mL = 2.70 mL
A 24.5 g sample of solution has a density of 0.768 g/mL. What is the sample
volume (in mL)?
, 31.9 mL
v = mass/density
v = 31.9 mL
In order to use a pipet, place a (1) at the top of the pipet. Use this object to fill the
pipet such that the (2) of the liquid is even with the volume line. Release the
liquid, touching the tip of the pipet to the side of the container if necessary to
release the last drop (3) the pipet tip.
1) Bulb or pump
2) Meniscus
3) Outside
Identify effective techniques for accurate pipet use.
1) Do not let liquid enter the pipet bulb or pump.
2) Measure liquid by aligning the meniscus with the volume line.
Accuracy
The closeness between a measurement and its accepted value.
Precision
The closeness among a set of measurements.
A series of measurements in the lab led to an experimental result of 32.9 mL, with
a calculated standard deviation of 0.3 mL. What is the standard way to report this
result?
32.9 ± 0.3 mL
A cube of plastic 1.3 × 10−5 km on a side has a mass of 2.1 g. What is its density
in g/cm3?
