1
CHEM 103 General Chemistry I Module 2 Lab Exam
Official Practice Exam 2026/2027 Complete Exam-Style
Questions with Detailed Rationales | 100% Verified | Pass
Guaranteed – A+ Graded
TABLE OF CONTENTS
Section 1 | Laboratory Safety & Fundamentals | Q1 – Q10
Section 2 | Measurement, Significant Figures & Density | Q11 – Q22
Section 3 | Separations and Purifications | Q23 – Q32
Section 4 | Quantitative Analysis & Titration | Q33 – Q42
Section 5 | NGN-Style Integrated Case Analysis | Q43 – Q50
Instructions: Choose the single best answer unless otherwise indicated.
For select-all-that-apply (SATA) questions, choose ALL correct options.
══════════════════════════════════════
SECTION 1: LABORATORY SAFETY & FUNDAMENTALS (Q1 –
Q10)
══════════════════════════════════════
Question 1 of 50
While preparing a solution of concentrated sulfuric acid, a student
accidentally splashes approximately 5 mL of acid onto their forearm
through a small tear in their nitrile glove. The skin shows immediate
,2
redness but no visible blistering yet. The eyewash station is 8 feet away,
and the safety shower is 15 feet away.
A. Remove the contaminated glove, flush the affected area at the
eyewash station for at least 15 minutes, then notify the instructor
B. Quickly neutralize the acid on the skin with sodium bicarbonate from
the lab bench before rinsing
C. Remove the glove, use the safety shower immediately since any acid
exposure requires full-body decontamination
D. Wipe off the excess acid with a paper towel first to minimize the
amount that needs to be rinsed away ✓ CORRECT
Correct Answer: A
Rationale: Chemical exposures to skin require immediate and prolonged
flushing with water—typically 15–20 minutes for corrosive acids—to
dilute and remove the chemical before it penetrates deeper tissue layers.
The eyewash station provides targeted flushing for localized exposures
like this forearm splash, whereas the safety shower is reserved for large-
area or clothing-saturated exposures. Choice D is dangerously incorrect
because wiping an acid spill spreads the chemical over a larger surface
area and delays critical water irrigation; never wipe corrosive
chemicals—always flush immediately.
Question 2 of 50
During a laboratory session focused on heating reactions in test tubes,
your lab partner holds a test tube containing 10 mL of aqueous sodium
,3
chloride solution directly over a Bunsen burner flame while looking
down into the opening of the tube to observe when boiling begins.
A. This procedure is acceptable as long as the test tube is held at a 45-
degree angle and moved continuously through the flame
B. The student should wear additional face protection and continue
observing closely since visual monitoring is essential for safety
C. This action violates two critical safety rules: test tubes should never
be pointed toward anyone (including oneself), and one should never look
down into an open vessel being heated ✓ CORRECT
D. The primary concern here is that sodium chloride solutions can
superheat and erupt violently, so a boiling chip should be added first
Correct Answer: C
Rationale: Heating any container while pointing the opening toward
yourself or others creates a projectile hazard if the contents boil over or
react unexpectedly; additionally, looking into any heated vessel risks
injury from splashing hot liquid or sudden pressure release. The correct
technique involves holding the test tube at an angle pointed away from
all personnel and observing the side or bottom of the tube for signs of
boiling. Choice A incorrectly suggests the angle alone resolves the
fundamental violation of looking into the opening, which remains
dangerous regardless of positioning.
Question 3 of 50
, 4
You arrive at your laboratory bench and notice a small puddle
(approximately 15 mL) of clear, odorless liquid on the floor near the
waste disposal area. You are uncertain whether this is water, an organic
solvent, or an aqueous chemical solution. No other students are currently
in the immediate vicinity.
A. Mop up the liquid with paper towels and dispose of them in the
regular trash since the volume is small and the liquid appears harmless
B. Alert the instructor immediately, cordon off the area to prevent others
from walking through it, and wait for guidance on appropriate cleanup
procedures ✓ CORRECT
C. Spray the area with water from the sink to dilute whatever chemical
might be present, then wipe it up with standard lab wipes
D. Locate the material Safety Data Sheet (SDS) binder, identify the
chemical by smell and appearance, and follow the prescribed cleanup
protocol independently
Correct Answer: B
Rationale: Unknown chemical spills should never be handled by
students without instructor authorization because the identity, hazards,
and appropriate neutralization or absorption methods cannot be
determined visually. The correct protocol involves immediate
notification of trained personnel, preventing access to the spill zone, and
allowing qualified individuals to assess and remediate the situation using
proper personal protective equipment and spill control materials. Choice
D is particularly dangerous because attempting to identify an unknown
chemical by smell introduces inhalation exposure risk and violates the
fundamental rule never to directly smell unknown substances.
CHEM 103 General Chemistry I Module 2 Lab Exam
Official Practice Exam 2026/2027 Complete Exam-Style
Questions with Detailed Rationales | 100% Verified | Pass
Guaranteed – A+ Graded
TABLE OF CONTENTS
Section 1 | Laboratory Safety & Fundamentals | Q1 – Q10
Section 2 | Measurement, Significant Figures & Density | Q11 – Q22
Section 3 | Separations and Purifications | Q23 – Q32
Section 4 | Quantitative Analysis & Titration | Q33 – Q42
Section 5 | NGN-Style Integrated Case Analysis | Q43 – Q50
Instructions: Choose the single best answer unless otherwise indicated.
For select-all-that-apply (SATA) questions, choose ALL correct options.
══════════════════════════════════════
SECTION 1: LABORATORY SAFETY & FUNDAMENTALS (Q1 –
Q10)
══════════════════════════════════════
Question 1 of 50
While preparing a solution of concentrated sulfuric acid, a student
accidentally splashes approximately 5 mL of acid onto their forearm
through a small tear in their nitrile glove. The skin shows immediate
,2
redness but no visible blistering yet. The eyewash station is 8 feet away,
and the safety shower is 15 feet away.
A. Remove the contaminated glove, flush the affected area at the
eyewash station for at least 15 minutes, then notify the instructor
B. Quickly neutralize the acid on the skin with sodium bicarbonate from
the lab bench before rinsing
C. Remove the glove, use the safety shower immediately since any acid
exposure requires full-body decontamination
D. Wipe off the excess acid with a paper towel first to minimize the
amount that needs to be rinsed away ✓ CORRECT
Correct Answer: A
Rationale: Chemical exposures to skin require immediate and prolonged
flushing with water—typically 15–20 minutes for corrosive acids—to
dilute and remove the chemical before it penetrates deeper tissue layers.
The eyewash station provides targeted flushing for localized exposures
like this forearm splash, whereas the safety shower is reserved for large-
area or clothing-saturated exposures. Choice D is dangerously incorrect
because wiping an acid spill spreads the chemical over a larger surface
area and delays critical water irrigation; never wipe corrosive
chemicals—always flush immediately.
Question 2 of 50
During a laboratory session focused on heating reactions in test tubes,
your lab partner holds a test tube containing 10 mL of aqueous sodium
,3
chloride solution directly over a Bunsen burner flame while looking
down into the opening of the tube to observe when boiling begins.
A. This procedure is acceptable as long as the test tube is held at a 45-
degree angle and moved continuously through the flame
B. The student should wear additional face protection and continue
observing closely since visual monitoring is essential for safety
C. This action violates two critical safety rules: test tubes should never
be pointed toward anyone (including oneself), and one should never look
down into an open vessel being heated ✓ CORRECT
D. The primary concern here is that sodium chloride solutions can
superheat and erupt violently, so a boiling chip should be added first
Correct Answer: C
Rationale: Heating any container while pointing the opening toward
yourself or others creates a projectile hazard if the contents boil over or
react unexpectedly; additionally, looking into any heated vessel risks
injury from splashing hot liquid or sudden pressure release. The correct
technique involves holding the test tube at an angle pointed away from
all personnel and observing the side or bottom of the tube for signs of
boiling. Choice A incorrectly suggests the angle alone resolves the
fundamental violation of looking into the opening, which remains
dangerous regardless of positioning.
Question 3 of 50
, 4
You arrive at your laboratory bench and notice a small puddle
(approximately 15 mL) of clear, odorless liquid on the floor near the
waste disposal area. You are uncertain whether this is water, an organic
solvent, or an aqueous chemical solution. No other students are currently
in the immediate vicinity.
A. Mop up the liquid with paper towels and dispose of them in the
regular trash since the volume is small and the liquid appears harmless
B. Alert the instructor immediately, cordon off the area to prevent others
from walking through it, and wait for guidance on appropriate cleanup
procedures ✓ CORRECT
C. Spray the area with water from the sink to dilute whatever chemical
might be present, then wipe it up with standard lab wipes
D. Locate the material Safety Data Sheet (SDS) binder, identify the
chemical by smell and appearance, and follow the prescribed cleanup
protocol independently
Correct Answer: B
Rationale: Unknown chemical spills should never be handled by
students without instructor authorization because the identity, hazards,
and appropriate neutralization or absorption methods cannot be
determined visually. The correct protocol involves immediate
notification of trained personnel, preventing access to the spill zone, and
allowing qualified individuals to assess and remediate the situation using
proper personal protective equipment and spill control materials. Choice
D is particularly dangerous because attempting to identify an unknown
chemical by smell introduces inhalation exposure risk and violates the
fundamental rule never to directly smell unknown substances.
