CHEM 101 Winter 2026 Exam 1 (A)
On the answer sheet (scantron) write your last name, first name initial (FI), middle name initial (MI) (if
applicable), Drexel ID number, and lab section number. Choose the best (most correct) answer for each
question and fill in the corresponding bubbles for all 26 questions. Look at the example of a correctly
filled bubble at the top of your scantron sheet. Do NOT go past the frame of the bubbles. DO NOT
CROSS OUT bubbles. DO NOT MARK/WRITE anything else on the scantron sheet.
Note: a copy of the periodic table has been provided at the end page of this exam.
Potentially useful data:
d= m/v
m=dv
Avogadro’s constant: 6.02 × 1023 mol-1
speed of light: c = 3.00 × 108 m/s
c=νλ
Ephoton = hν
1 Hz = 1 s-1
Planck’s constant: h = 6.63 × 10-34 J∙s
Questions:
1.Please choose the letter “A” as your answer for this question.
2. Which statement is true:
A) P4 is not a molecule.
B) A piece of pure aluminum which has millions of aluminum atoms is an element.
C)Water (H2O) is a compound but not a molecule.
D)Salt (NaCl) cannot be a pure compound since it has sodium (Na) and chlorine (Cl).
E) None of them
Answer: B
3. Which of the following is the SMALLEST volume?
A) 2.6 cm3
B) 0.065 dL
C) 3.5 × 102 mL
D) 9.0 × 106 nL
E) 1.2 x 10 -2 L
Answer: A
4. How are gases different from solids and liquids?
A) Gases can only be made up of atoms.
B) The particles in a gas attract each other much more strongly than in solids and liquids.
C) Gases are compressible.
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,D) Only gases can take the shape of their container.
E) Gases are colorless.
Answer: C
5. Determine the mass of an object that has a volume of 88.6 mL and a density of 7.77 g/mL.
A) 96.4 g
B) 0.0877 g
C) 11.4 g
D) 80.8 g
E) 688 g
Answer: E
6. Two or more substances in variable proportions, where the composition is constant throughout are
A) a compound.
B) an element.
C) a heterogeneous mixture.
D) a homogeneous mixture.
E) a crystalline solid.
Answer: D
7. An element has three stable isotopes with masses of 27.977 amu, 28.976 amu, and 29.973 amu. The
heavier two isotopes have an abundance of 4.68% and 3.09%, respectively. What is the mass of the
element?
A) 27.684 amu
B) 29.251 amu
C) 28.085 amu
D) 30.107 amu
E) 28.991 amu
Answer: C
8. Dalton's Atomic Theory states
A) that all elements have several isotopes.
B) that matter is composed of small indestructible particles.
C) that the properties of matter are determined by the properties of atoms.
D) that energy is neither created nor destroyed during a chemical reaction.
E) that an atom is predominantly empty space.
Answer: B
9. Which of the following is an example of the law of multiple proportions?
A) A sample of chlorine is found to contain three times as much Cl-35 as Cl-37.
B) Two different compounds formed from carbon and oxygen have the following mass ratios:
1.33 g O: 1 g C and 2.66 g O: 1 g C.
C) Two different samples of table salt are found to have the same ratio of sodium to chlorine.
D) The atomic mass of bromine is found to be 79.90 amu.
E) Nitrogen dioxide always has a mass ratio of 2.28 g O: 1 g N.
Answer: B
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,10. An atom has 34 protons, 44 neutrons, and 34 electrons. Identify the element made of such atoms.
a) 68Er
b) 48Cd
c) 32Ge
d) 78Se
e) 44Ru
Answer: d
11. Which of the following statements about subatomic particles is TRUE?
A) A neutral atom contains the same number of protons and electrons.
B) Protons have about the same mass as electrons.
C) Electrons make up most of the mass of an atom.
D) Protons and neutrons have opposite, but equal in magnitude, charges.
E) Neutrons and electrons are found in the nucleus of an atom.
Answer: A
12. Find the correct combination of protons and electrons for S2-?
A) 16 protons and 14 electrons
B) 34 protons and 32 electrons
C) 16 protons and 18 electrons
D) 18 protons and 18 electrons
E) 34 protons and 36 electrons
Answer: C
13. A certain mass of carbon reacts with 13.6 g of oxygen to form carbon monoxide, CO. How many
grams of oxygen would react with that same mass of carbon to form carbon dioxide, CO2?
a) 6.80 g
b) 27.2 g
c) 25.6 g
d) 13.6 g
e) 2.00 g
Answer: B
14. In the table below, identify the row that correctly lists Atom A and Atom B as isotopes.
Atom A Atom B
+ - +
a) 6p 7n 6e 7p 6n 6 e-
b) 33 p+ 34 n 35 e- 35 p+ 34 n 33 e-
c) 15p+ 18 n 15 e- 15 p+ 18 n 18 e-
d) 22 p+ 24 n 20 e- 23 p+ 24 n 20 e-
e) 16 p+ 18 n 16 e- 16 p+ 17 n 16 e-
Answer: E
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, 15. How many complete cycles per second will a wave with a frequency of 2 Hz make?
A) 2
B) 1
C) 0.5
D) 0.25
E) 4
Answer: A
16. How many iron atoms are contained in 3.54 x 10-1 kg of iron? (atomic mass of iron: 56 g/mol)
A) 2.62 × 1025 Fe atoms
B) 2.13 × 1026 Fe atoms
C) 4.69 × 1024 Fe atoms
D) 3.82 × 1024 Fe atoms
E) 9.50 × 1022 Fe atoms
Answer: D
17. Choose the heterogeneous mixture from the list below.
A) sugar water
B) air
C) sand water
D) cup of coffee
E) natural gas
Answer: C
18. An ion has 12 protons, 14 neutrons, and 10 electrons. The symbol for the ion is
A) 26Mg2+
B) 26Mg2-
C) 24Si2+
D) 24Si2-
E) 26Ne2-
Answer: A
19. How many carbon atoms are contained in 3.75 moles of carbon?
A) 1.23 × 1024 carbon atoms
B) 2.26 × 1024 carbon atoms
C) 1.61 × 1023 carbon atoms
D) 5.48 × 1025 carbon atoms
E) 6.50 × 1025 carbon atoms
Answer: B
20. On the electromagnetic spectrum, visible light is immediately between two other wavelengths. Name
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On the answer sheet (scantron) write your last name, first name initial (FI), middle name initial (MI) (if
applicable), Drexel ID number, and lab section number. Choose the best (most correct) answer for each
question and fill in the corresponding bubbles for all 26 questions. Look at the example of a correctly
filled bubble at the top of your scantron sheet. Do NOT go past the frame of the bubbles. DO NOT
CROSS OUT bubbles. DO NOT MARK/WRITE anything else on the scantron sheet.
Note: a copy of the periodic table has been provided at the end page of this exam.
Potentially useful data:
d= m/v
m=dv
Avogadro’s constant: 6.02 × 1023 mol-1
speed of light: c = 3.00 × 108 m/s
c=νλ
Ephoton = hν
1 Hz = 1 s-1
Planck’s constant: h = 6.63 × 10-34 J∙s
Questions:
1.Please choose the letter “A” as your answer for this question.
2. Which statement is true:
A) P4 is not a molecule.
B) A piece of pure aluminum which has millions of aluminum atoms is an element.
C)Water (H2O) is a compound but not a molecule.
D)Salt (NaCl) cannot be a pure compound since it has sodium (Na) and chlorine (Cl).
E) None of them
Answer: B
3. Which of the following is the SMALLEST volume?
A) 2.6 cm3
B) 0.065 dL
C) 3.5 × 102 mL
D) 9.0 × 106 nL
E) 1.2 x 10 -2 L
Answer: A
4. How are gases different from solids and liquids?
A) Gases can only be made up of atoms.
B) The particles in a gas attract each other much more strongly than in solids and liquids.
C) Gases are compressible.
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,D) Only gases can take the shape of their container.
E) Gases are colorless.
Answer: C
5. Determine the mass of an object that has a volume of 88.6 mL and a density of 7.77 g/mL.
A) 96.4 g
B) 0.0877 g
C) 11.4 g
D) 80.8 g
E) 688 g
Answer: E
6. Two or more substances in variable proportions, where the composition is constant throughout are
A) a compound.
B) an element.
C) a heterogeneous mixture.
D) a homogeneous mixture.
E) a crystalline solid.
Answer: D
7. An element has three stable isotopes with masses of 27.977 amu, 28.976 amu, and 29.973 amu. The
heavier two isotopes have an abundance of 4.68% and 3.09%, respectively. What is the mass of the
element?
A) 27.684 amu
B) 29.251 amu
C) 28.085 amu
D) 30.107 amu
E) 28.991 amu
Answer: C
8. Dalton's Atomic Theory states
A) that all elements have several isotopes.
B) that matter is composed of small indestructible particles.
C) that the properties of matter are determined by the properties of atoms.
D) that energy is neither created nor destroyed during a chemical reaction.
E) that an atom is predominantly empty space.
Answer: B
9. Which of the following is an example of the law of multiple proportions?
A) A sample of chlorine is found to contain three times as much Cl-35 as Cl-37.
B) Two different compounds formed from carbon and oxygen have the following mass ratios:
1.33 g O: 1 g C and 2.66 g O: 1 g C.
C) Two different samples of table salt are found to have the same ratio of sodium to chlorine.
D) The atomic mass of bromine is found to be 79.90 amu.
E) Nitrogen dioxide always has a mass ratio of 2.28 g O: 1 g N.
Answer: B
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,10. An atom has 34 protons, 44 neutrons, and 34 electrons. Identify the element made of such atoms.
a) 68Er
b) 48Cd
c) 32Ge
d) 78Se
e) 44Ru
Answer: d
11. Which of the following statements about subatomic particles is TRUE?
A) A neutral atom contains the same number of protons and electrons.
B) Protons have about the same mass as electrons.
C) Electrons make up most of the mass of an atom.
D) Protons and neutrons have opposite, but equal in magnitude, charges.
E) Neutrons and electrons are found in the nucleus of an atom.
Answer: A
12. Find the correct combination of protons and electrons for S2-?
A) 16 protons and 14 electrons
B) 34 protons and 32 electrons
C) 16 protons and 18 electrons
D) 18 protons and 18 electrons
E) 34 protons and 36 electrons
Answer: C
13. A certain mass of carbon reacts with 13.6 g of oxygen to form carbon monoxide, CO. How many
grams of oxygen would react with that same mass of carbon to form carbon dioxide, CO2?
a) 6.80 g
b) 27.2 g
c) 25.6 g
d) 13.6 g
e) 2.00 g
Answer: B
14. In the table below, identify the row that correctly lists Atom A and Atom B as isotopes.
Atom A Atom B
+ - +
a) 6p 7n 6e 7p 6n 6 e-
b) 33 p+ 34 n 35 e- 35 p+ 34 n 33 e-
c) 15p+ 18 n 15 e- 15 p+ 18 n 18 e-
d) 22 p+ 24 n 20 e- 23 p+ 24 n 20 e-
e) 16 p+ 18 n 16 e- 16 p+ 17 n 16 e-
Answer: E
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, 15. How many complete cycles per second will a wave with a frequency of 2 Hz make?
A) 2
B) 1
C) 0.5
D) 0.25
E) 4
Answer: A
16. How many iron atoms are contained in 3.54 x 10-1 kg of iron? (atomic mass of iron: 56 g/mol)
A) 2.62 × 1025 Fe atoms
B) 2.13 × 1026 Fe atoms
C) 4.69 × 1024 Fe atoms
D) 3.82 × 1024 Fe atoms
E) 9.50 × 1022 Fe atoms
Answer: D
17. Choose the heterogeneous mixture from the list below.
A) sugar water
B) air
C) sand water
D) cup of coffee
E) natural gas
Answer: C
18. An ion has 12 protons, 14 neutrons, and 10 electrons. The symbol for the ion is
A) 26Mg2+
B) 26Mg2-
C) 24Si2+
D) 24Si2-
E) 26Ne2-
Answer: A
19. How many carbon atoms are contained in 3.75 moles of carbon?
A) 1.23 × 1024 carbon atoms
B) 2.26 × 1024 carbon atoms
C) 1.61 × 1023 carbon atoms
D) 5.48 × 1025 carbon atoms
E) 6.50 × 1025 carbon atoms
Answer: B
20. On the electromagnetic spectrum, visible light is immediately between two other wavelengths. Name
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