CHEM 121 LAB REPORTS 3 COMPREHENSIVE
STUDY GUIDE 2026 PRACTICE QUESTIONS
AND ACCURATE ANSWERS GRADED A+
◉ 5.43 g Answer: A balance with ±0.01 g tolerance
◉ 1.230 g Answer: A balance with ±0.001 g tolerance
◉ 4.0000 g Answer: 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? Answer: 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)? Answer: 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. Answer: 1) Bulb or pump
2) Meniscus
3) Outside
◉ Identify effective techniques for accurate pipet use. Answer: 1) Do
not let liquid enter the pipet bulb or pump.
2) Measure liquid by aligning the meniscus with the volume line.
◉ Accuracy Answer: The closeness between a measurement and its
accepted value.
◉ Precision Answer: 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? Answer: 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? Answer: 0.96 g/cm^3
(PL Question #1 - Exp 1)
STUDY GUIDE 2026 PRACTICE QUESTIONS
AND ACCURATE ANSWERS GRADED A+
◉ 5.43 g Answer: A balance with ±0.01 g tolerance
◉ 1.230 g Answer: A balance with ±0.001 g tolerance
◉ 4.0000 g Answer: 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? Answer: 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)? Answer: 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. Answer: 1) Bulb or pump
2) Meniscus
3) Outside
◉ Identify effective techniques for accurate pipet use. Answer: 1) Do
not let liquid enter the pipet bulb or pump.
2) Measure liquid by aligning the meniscus with the volume line.
◉ Accuracy Answer: The closeness between a measurement and its
accepted value.
◉ Precision Answer: 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? Answer: 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? Answer: 0.96 g/cm^3
(PL Question #1 - Exp 1)
