CHEM 120 EXAM 1 (CHAMBERLAIN) NEWEST 2026
ACTUAL EXAM TEST BANK| CHEM 120
INTRODUCTION TO GENERAL, ORGANIC &
BIOLOGICAL CHEMISTRY EXAM 1 REVIEW WITH 350
REAL EXAM QUESTIONS AND CORRECT VERIFIED
ANSWERS/ GRADED A+ (MOST RECENT!!)
Q1. How many significant figures are in the measurement
0.004050 m?
A) 3
B) 4
C) 5
D) 6
Correct Answer: B
Rationale: Leading zeros are not significant. 0.004050 → digits
4,0,5,0 are significant (the trailing zero after the decimal counts).
4 significant figures.
Q2. What is the result of 12.34 + 5.6 rounded to the correct
number of decimal places?
A) 17.9
1
,B) 18.0
C) 17.94
D) 17.9
Correct Answer: D
Rationale: 12.34 (2 decimal) + 5.6 (1 decimal) = 17.94. Round
to least precise decimal place (tenths) → 17.9.
Q3. Convert 25.0°C to Kelvin.
A) 248 K
B) 273 K
C) 298 K
D) 298.15 K
Correct Answer: C
Rationale: K = °C + 273.15. 25.0 + 273.15 = 298.15 K. With
3 significant figures → 298 K.
Q4. Which subatomic particle has a negative charge and
negligible mass?
A) Proton
B) Neutron
2
,C) Electron
D) Positron
Correct Answer: C
Rationale: Electrons have a charge of –1 and mass ~1/1836
amu. Protons positive, neutrons neutral.
Q5. What is the density of a substance with mass 15.0 g and
volume 5.0 mL?
A) 0.33 g/mL
B) 3.0 g/mL
C) 10.0 g/mL
D) 75 g/mL
Correct Answer: B
Rationale: Density = mass/volume = 15.0 g / 5.0 mL = 3.0
g/mL (2 significant figures from 5.0 mL).
Q6. How many protons, neutrons, and electrons are in
⁴⁰Ca²⁺?
A) 20 p, 20 n, 18 e
B) 20 p, 20 n, 20 e
3
, C) 20 p, 20 n, 22 e
D) 40 p, 20 n, 20 e
Correct Answer: A
Rationale: Atomic number 20 → 20 protons. Mass number 40 →
neutrons = 40 – 20 = 20. Ca²⁺ has lost 2 electrons → 20 – 2 =
18 electrons.
Q7. Which element is a noble gas?
A) Oxygen (O)
B) Neon (Ne)
C) Chlorine (Cl)
D) Nitrogen (N)
Correct Answer: B
Rationale: Noble gases are Group 18: He, Ne, Ar, Kr, Xe, Rn.
Neon is a noble gas. Oxygen is Group 16, Chlorine Group 17,
Nitrogen Group 15.
Q8. Convert 3.5 km to meters.
A) 35 m
B) 350 m
4
ACTUAL EXAM TEST BANK| CHEM 120
INTRODUCTION TO GENERAL, ORGANIC &
BIOLOGICAL CHEMISTRY EXAM 1 REVIEW WITH 350
REAL EXAM QUESTIONS AND CORRECT VERIFIED
ANSWERS/ GRADED A+ (MOST RECENT!!)
Q1. How many significant figures are in the measurement
0.004050 m?
A) 3
B) 4
C) 5
D) 6
Correct Answer: B
Rationale: Leading zeros are not significant. 0.004050 → digits
4,0,5,0 are significant (the trailing zero after the decimal counts).
4 significant figures.
Q2. What is the result of 12.34 + 5.6 rounded to the correct
number of decimal places?
A) 17.9
1
,B) 18.0
C) 17.94
D) 17.9
Correct Answer: D
Rationale: 12.34 (2 decimal) + 5.6 (1 decimal) = 17.94. Round
to least precise decimal place (tenths) → 17.9.
Q3. Convert 25.0°C to Kelvin.
A) 248 K
B) 273 K
C) 298 K
D) 298.15 K
Correct Answer: C
Rationale: K = °C + 273.15. 25.0 + 273.15 = 298.15 K. With
3 significant figures → 298 K.
Q4. Which subatomic particle has a negative charge and
negligible mass?
A) Proton
B) Neutron
2
,C) Electron
D) Positron
Correct Answer: C
Rationale: Electrons have a charge of –1 and mass ~1/1836
amu. Protons positive, neutrons neutral.
Q5. What is the density of a substance with mass 15.0 g and
volume 5.0 mL?
A) 0.33 g/mL
B) 3.0 g/mL
C) 10.0 g/mL
D) 75 g/mL
Correct Answer: B
Rationale: Density = mass/volume = 15.0 g / 5.0 mL = 3.0
g/mL (2 significant figures from 5.0 mL).
Q6. How many protons, neutrons, and electrons are in
⁴⁰Ca²⁺?
A) 20 p, 20 n, 18 e
B) 20 p, 20 n, 20 e
3
, C) 20 p, 20 n, 22 e
D) 40 p, 20 n, 20 e
Correct Answer: A
Rationale: Atomic number 20 → 20 protons. Mass number 40 →
neutrons = 40 – 20 = 20. Ca²⁺ has lost 2 electrons → 20 – 2 =
18 electrons.
Q7. Which element is a noble gas?
A) Oxygen (O)
B) Neon (Ne)
C) Chlorine (Cl)
D) Nitrogen (N)
Correct Answer: B
Rationale: Noble gases are Group 18: He, Ne, Ar, Kr, Xe, Rn.
Neon is a noble gas. Oxygen is Group 16, Chlorine Group 17,
Nitrogen Group 15.
Q8. Convert 3.5 km to meters.
A) 35 m
B) 350 m
4
