CHM 2045L General Chemistry 1
Laboratory Exam Practice Questions
And Correct Answers (Verified Answers)
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1. In a General Chemistry I laboratory, which practice is most important for
preventing contamination when transferring a liquid reagent from a reagent
bottle into a test tube?
A. Pouring the reagent directly from the test tube back into the reagent
bottle after use
B. Using the same dropper for all reagents provided that it appears clean
C. Touching the dropper tip to the inside of the test tube to ensure complete
transfer
D. Using a clean, appropriate transfer device and preventing the reagent
container or dropper from contacting the experimental sample
The correct practice prevents cross-contamination between reagents and
samples, which could alter experimental results and create safety hazards.
2. A student needs to measure exactly 25.00 mL of a solution for a
quantitative experiment. Which piece of glassware is most
appropriate?
A. 50-mL beaker
B. 100-mL graduated cylinder
C. 25-mL volumetric pipette
D. 250-mL Erlenmeyer flask
,A volumetric pipette is calibrated to deliver a highly accurate fixed volume
and is therefore preferred when precise quantitative transfer is required.
3. When reading the volume of a colorless aqueous solution in a
graduated cylinder, where should the student's eye be positioned?
A. Above the meniscus
B. Below the meniscus
C. At the same level as the bottom of the meniscus
D. At the top of the cylinder
Reading at eye level with the bottom of the meniscus minimizes parallax
error and provides the most accurate volume measurement for a typical
aqueous solution.
4. Which statement correctly describes the proper procedure for heating
a liquid in a test tube?
A. Point the mouth of the test tube toward yourself so that you can
observe the liquid closely
B. Seal the test tube with a stopper during heating
C. Hold the test tube stationary directly in the hottest part of the
flame
D. Point the mouth away from yourself and others while
continuously moving the test tube through the heated region
Liquids can suddenly boil or eject material during heating, so directing the
opening away from people and distributing heat reduces the risk of injury.
5. A student spills a concentrated acid on the laboratory bench. What
should be done first?
A. Wipe it immediately with bare hands
B. Add water directly and leave the area unattended
C. Notify the instructor and follow the laboratory's prescribed spill-
response procedure
D. Cover it with paper towels and continue working
,Concentrated acids can cause severe chemical burns and hazardous
reactions, so spills must be handled according to established laboratory
safety procedures rather than improvised cleanup.
6. Which measurement generally has the greatest precision for
determining the volume of a liquid?
A. 100-mL beaker marked approximately every 20 mL
B. 100-mL graduated cylinder marked every 1 mL
C. 25.00-mL volumetric pipette
D. 250-mL Erlenmeyer flask marked approximately every 25 mL
Volumetric pipettes are manufactured and calibrated for highly precise
delivery of a specified volume, making them more precise than general-
purpose containers.
7. A student records the mass of an empty crucible as 24.631 g and the
mass of the crucible containing a solid sample as 26.874 g. What is the
mass of the solid?
A. 51.505 g
B. 2.875 g
C. 2.243 g
D. 0.243 g
The sample mass is obtained by subtraction: 26.874 g − 24.631 g = 2.243 g.
8. Which type of error is most directly associated with a balance that
consistently reads 0.15 g too high?
A. Random error
B. Gross experimental error
C. Systematic error
D. Sampling error
A consistent bias in the same direction is characteristic of systematic error,
often resulting from calibration or instrument problems.
9. A student obtains the following density measurements for a
substance: 2.71, 2.70, 2.71, and 2.70 g/mL. The accepted value is 2.70
, g/mL. What conclusion is most appropriate?
A. The measurements are neither precise nor accurate
B. The measurements are accurate but not precise
C. The measurements are both relatively precise and accurate
D. The measurements are precise but completely inaccurate
The measurements cluster closely together, indicating precision, and they
are close to the accepted value, indicating accuracy.
10. Which expression correctly represents density?
A. Density = volume × mass
B. Density = volume/mass
C. Density = mass/volume
D. Density = mass + volume
Density is defined as the amount of mass contained per unit volume,
commonly expressed in g/mL or g/cm³.
11. A metal sample has a mass of 54.0 g and occupies 20.0 mL. What
is its density?
A. 0.370 g/mL
B. 1.85 g/mL
C. 2.70 g/mL
D. 74.0 g/mL
Using density = mass/volume gives 54.0 g ÷ 20.0 mL = 2.70 g/mL.
12. Which technique is most appropriate for determining the
volume of an irregularly shaped solid that does not dissolve in water?
A. Measuring its dimensions with a ruler and assuming it is a
rectangular prism
B. Measuring the volume of an empty beaker
C. Using water displacement in a graduated cylinder
D. Heating it until its volume changes
Water displacement determines the volume of an irregular object from the
increase in water level after the object is submerged.
Laboratory Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
Download Pdf.
1. In a General Chemistry I laboratory, which practice is most important for
preventing contamination when transferring a liquid reagent from a reagent
bottle into a test tube?
A. Pouring the reagent directly from the test tube back into the reagent
bottle after use
B. Using the same dropper for all reagents provided that it appears clean
C. Touching the dropper tip to the inside of the test tube to ensure complete
transfer
D. Using a clean, appropriate transfer device and preventing the reagent
container or dropper from contacting the experimental sample
The correct practice prevents cross-contamination between reagents and
samples, which could alter experimental results and create safety hazards.
2. A student needs to measure exactly 25.00 mL of a solution for a
quantitative experiment. Which piece of glassware is most
appropriate?
A. 50-mL beaker
B. 100-mL graduated cylinder
C. 25-mL volumetric pipette
D. 250-mL Erlenmeyer flask
,A volumetric pipette is calibrated to deliver a highly accurate fixed volume
and is therefore preferred when precise quantitative transfer is required.
3. When reading the volume of a colorless aqueous solution in a
graduated cylinder, where should the student's eye be positioned?
A. Above the meniscus
B. Below the meniscus
C. At the same level as the bottom of the meniscus
D. At the top of the cylinder
Reading at eye level with the bottom of the meniscus minimizes parallax
error and provides the most accurate volume measurement for a typical
aqueous solution.
4. Which statement correctly describes the proper procedure for heating
a liquid in a test tube?
A. Point the mouth of the test tube toward yourself so that you can
observe the liquid closely
B. Seal the test tube with a stopper during heating
C. Hold the test tube stationary directly in the hottest part of the
flame
D. Point the mouth away from yourself and others while
continuously moving the test tube through the heated region
Liquids can suddenly boil or eject material during heating, so directing the
opening away from people and distributing heat reduces the risk of injury.
5. A student spills a concentrated acid on the laboratory bench. What
should be done first?
A. Wipe it immediately with bare hands
B. Add water directly and leave the area unattended
C. Notify the instructor and follow the laboratory's prescribed spill-
response procedure
D. Cover it with paper towels and continue working
,Concentrated acids can cause severe chemical burns and hazardous
reactions, so spills must be handled according to established laboratory
safety procedures rather than improvised cleanup.
6. Which measurement generally has the greatest precision for
determining the volume of a liquid?
A. 100-mL beaker marked approximately every 20 mL
B. 100-mL graduated cylinder marked every 1 mL
C. 25.00-mL volumetric pipette
D. 250-mL Erlenmeyer flask marked approximately every 25 mL
Volumetric pipettes are manufactured and calibrated for highly precise
delivery of a specified volume, making them more precise than general-
purpose containers.
7. A student records the mass of an empty crucible as 24.631 g and the
mass of the crucible containing a solid sample as 26.874 g. What is the
mass of the solid?
A. 51.505 g
B. 2.875 g
C. 2.243 g
D. 0.243 g
The sample mass is obtained by subtraction: 26.874 g − 24.631 g = 2.243 g.
8. Which type of error is most directly associated with a balance that
consistently reads 0.15 g too high?
A. Random error
B. Gross experimental error
C. Systematic error
D. Sampling error
A consistent bias in the same direction is characteristic of systematic error,
often resulting from calibration or instrument problems.
9. A student obtains the following density measurements for a
substance: 2.71, 2.70, 2.71, and 2.70 g/mL. The accepted value is 2.70
, g/mL. What conclusion is most appropriate?
A. The measurements are neither precise nor accurate
B. The measurements are accurate but not precise
C. The measurements are both relatively precise and accurate
D. The measurements are precise but completely inaccurate
The measurements cluster closely together, indicating precision, and they
are close to the accepted value, indicating accuracy.
10. Which expression correctly represents density?
A. Density = volume × mass
B. Density = volume/mass
C. Density = mass/volume
D. Density = mass + volume
Density is defined as the amount of mass contained per unit volume,
commonly expressed in g/mL or g/cm³.
11. A metal sample has a mass of 54.0 g and occupies 20.0 mL. What
is its density?
A. 0.370 g/mL
B. 1.85 g/mL
C. 2.70 g/mL
D. 74.0 g/mL
Using density = mass/volume gives 54.0 g ÷ 20.0 mL = 2.70 g/mL.
12. Which technique is most appropriate for determining the
volume of an irregularly shaped solid that does not dissolve in water?
A. Measuring its dimensions with a ruler and assuming it is a
rectangular prism
B. Measuring the volume of an empty beaker
C. Using water displacement in a graduated cylinder
D. Heating it until its volume changes
Water displacement determines the volume of an irregular object from the
increase in water level after the object is submerged.
