CHEM 111 General Chemistry I Final Exam
Preparation Guide
Comprehensive Practice Questions & Solutions (58 Questions)
This study guide covers fundamental concepts in General Chemistry I, including atomic
structure, periodic trends, chemical bonding, molecular geometry, stoichiometry, solution
chemistry, thermochemistry, and gas laws.
Section 1: Matter, Measurement, and Atomic Structure
1. A piece of metal has a mass of 45.0 g and displaces 5.0 mL of water in a graduated
cylinder. What is the density of the metal?
A) 0.11 g/mL
B) 9.0 g/mL
C) 225 g/mL
D) 40.0 g/mL
Explanation: Density is calculated by dividing mass by volume (45.0 g / 5.0 mL = 9.0 g/mL).
Students often multiply instead of divide, leading to incorrect high values like 225.
2. How many significant figures are in the measurement 0.004050 grams?
A) 3
B) 6
C) 4
D) 5
Explanation: Leading zeros before the first non-zero digit are never significant, while trailing
zeros after a decimal point count. That leaves four significant digits (4, 0, 5, 0).
3. An neutral atom of Carbon-14 contains how many protons, neutrons, and electrons?
A) 6 protons, 8 neutrons, 6 electrons
B) 6 protons, 6 neutrons, 8 electrons
C) 8 protons, 6 neutrons, 6 electrons
D) 14 protons, 6 neutrons, 14 electrons
Explanation: Carbon always has an atomic number of 6, meaning 6 protons and 6 electrons
in a neutral atom. Subtracting 6 from the mass number 14 gives 8 neutrons.
4. Which subatomic particle was discovered by J.J. Thomson using cathode ray tubes?
, A) Proton
B) Neutron
C) Alpha particle
D) Electron
Explanation: Thomson's cathode ray experiment demonstrated that rays were deflected by
electrical fields, proving the existence of negatively charged electrons. Rutherford later
discovered the proton and dense nucleus.
5. Chlorine has two naturally occurring isotopes: Cl-35 (mass = 34.97 amu, abundance =
75.78%) and Cl-37 (mass = 36.97 amu, abundance = 24.22%). What is the average atomic
mass of chlorine?
A) 36.00 amu
B) 35.45 amu
C) 35.97 amu
D) 34.97 amu
Explanation: Multiply each isotopic mass by its decimal abundance and add them together:
(34.97 x 0.7578) + (36.97 x 0.2422) = 35.45 amu. Simply averaging the two mass numbers
ignores the higher abundance of Cl-35.
6. Which classification describes brass, a uniform mixture of copper and zinc?
A) Heterogeneous mixture
B) Pure compound
C) Homogeneous mixture
D) Pure element
Explanation: Brass is a solid solution (an alloy) with an even composition throughout,
making it a homogeneous mixture. Compounds require chemical bonding in fixed whole-
number ratios.
7. Which process represents a chemical change rather than a physical change?
A) Boiling ethanol into gas
B) Dissolving sugar in warm water
C) Crushing ice into slush
D) Iron rusting in humid air
Explanation: Rusting forms a new substance (iron oxide) with completely different chemical
properties. Phase changes and dissolving alter physical form without changing molecular
identity.
Section 2: Nomenclature, Moles, and Stiochiometry
Preparation Guide
Comprehensive Practice Questions & Solutions (58 Questions)
This study guide covers fundamental concepts in General Chemistry I, including atomic
structure, periodic trends, chemical bonding, molecular geometry, stoichiometry, solution
chemistry, thermochemistry, and gas laws.
Section 1: Matter, Measurement, and Atomic Structure
1. A piece of metal has a mass of 45.0 g and displaces 5.0 mL of water in a graduated
cylinder. What is the density of the metal?
A) 0.11 g/mL
B) 9.0 g/mL
C) 225 g/mL
D) 40.0 g/mL
Explanation: Density is calculated by dividing mass by volume (45.0 g / 5.0 mL = 9.0 g/mL).
Students often multiply instead of divide, leading to incorrect high values like 225.
2. How many significant figures are in the measurement 0.004050 grams?
A) 3
B) 6
C) 4
D) 5
Explanation: Leading zeros before the first non-zero digit are never significant, while trailing
zeros after a decimal point count. That leaves four significant digits (4, 0, 5, 0).
3. An neutral atom of Carbon-14 contains how many protons, neutrons, and electrons?
A) 6 protons, 8 neutrons, 6 electrons
B) 6 protons, 6 neutrons, 8 electrons
C) 8 protons, 6 neutrons, 6 electrons
D) 14 protons, 6 neutrons, 14 electrons
Explanation: Carbon always has an atomic number of 6, meaning 6 protons and 6 electrons
in a neutral atom. Subtracting 6 from the mass number 14 gives 8 neutrons.
4. Which subatomic particle was discovered by J.J. Thomson using cathode ray tubes?
, A) Proton
B) Neutron
C) Alpha particle
D) Electron
Explanation: Thomson's cathode ray experiment demonstrated that rays were deflected by
electrical fields, proving the existence of negatively charged electrons. Rutherford later
discovered the proton and dense nucleus.
5. Chlorine has two naturally occurring isotopes: Cl-35 (mass = 34.97 amu, abundance =
75.78%) and Cl-37 (mass = 36.97 amu, abundance = 24.22%). What is the average atomic
mass of chlorine?
A) 36.00 amu
B) 35.45 amu
C) 35.97 amu
D) 34.97 amu
Explanation: Multiply each isotopic mass by its decimal abundance and add them together:
(34.97 x 0.7578) + (36.97 x 0.2422) = 35.45 amu. Simply averaging the two mass numbers
ignores the higher abundance of Cl-35.
6. Which classification describes brass, a uniform mixture of copper and zinc?
A) Heterogeneous mixture
B) Pure compound
C) Homogeneous mixture
D) Pure element
Explanation: Brass is a solid solution (an alloy) with an even composition throughout,
making it a homogeneous mixture. Compounds require chemical bonding in fixed whole-
number ratios.
7. Which process represents a chemical change rather than a physical change?
A) Boiling ethanol into gas
B) Dissolving sugar in warm water
C) Crushing ice into slush
D) Iron rusting in humid air
Explanation: Rusting forms a new substance (iron oxide) with completely different chemical
properties. Phase changes and dissolving alter physical form without changing molecular
identity.
Section 2: Nomenclature, Moles, and Stiochiometry
