CHEM 120 Final Exam Review
Practice Questions
Question 1
What is the basic unit of matter?
A. Molecule
B. Atom
C. Compound
D. Element
Answer: B. Atom
Rationale: The atom is the basic unit of matter and the smallest particle of an element
that retains its properties .
Question 2
Which state of matter has a definite volume but no definite shape?
A. Solid
B. Liquid
C. Gas
D. Plasma
Answer: B. Liquid
Rationale: Liquids have a definite volume (they don't expand to fill the container) but
take the shape of their container (no definite shape). Solids have definite shape and
volume; gases have neither .
,Question 3
What is the normal body temperature in Kelvin?
A. 273 K
B. 310 K
C. 298 K
D. 373 K
Answer: B. 310 K
Rationale: Normal body temperature is 98.6°F or 37°C. K = 37 + 273.15 = 310.15 K
(approximately 310 K).
Question 4
What is the boiling point of water on the Kelvin scale?
A. 273 K
B. 298 K
C. 310 K
D. 373 K
Answer: D. 373 K
Rationale: Water boils at 100°C. K = 100 + 273.15 = 373.15 K.
Question 5
What is the density of a substance with a mass of 50 g and a volume of 25 mL?
A. 1.0 g/mL
B. 2.0 g/mL
C. 0.5 g/mL
D. 4.0 g/mL
Answer: B. 2.0 g/mL
Rationale: Density = Mass / Volume = 50 g / 25 mL = 2.0 g/mL.
, Section 2: Atoms, Ions, and Periodic Table
Subatomic Particles
Particle Location Charge Mass
Proton Nucleus +1 1 amu
Neutron Nucleus 0 1 amu
Electron Outside nucleus -1 ~0 amu
Atomic Calculations
Calculation Formula
Atomic Number # of Protons
Mass Number Protons + Neutrons
# of Neutrons Mass Number - Atomic Number
# of Electrons (neutral) # of Protons
Isotopes
Atoms with the same number of protons (same element) but different numbers of
neutrons
Example: Carbon-12 and Carbon-14 both have 6 protons; Carbon-12 has 6 neutrons,
Carbon-14 has 8 neutrons
Electron Configuration
Electrons fill orbitals in order of increasing energy: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, etc.
Practice Questions
Question 1
What is the basic unit of matter?
A. Molecule
B. Atom
C. Compound
D. Element
Answer: B. Atom
Rationale: The atom is the basic unit of matter and the smallest particle of an element
that retains its properties .
Question 2
Which state of matter has a definite volume but no definite shape?
A. Solid
B. Liquid
C. Gas
D. Plasma
Answer: B. Liquid
Rationale: Liquids have a definite volume (they don't expand to fill the container) but
take the shape of their container (no definite shape). Solids have definite shape and
volume; gases have neither .
,Question 3
What is the normal body temperature in Kelvin?
A. 273 K
B. 310 K
C. 298 K
D. 373 K
Answer: B. 310 K
Rationale: Normal body temperature is 98.6°F or 37°C. K = 37 + 273.15 = 310.15 K
(approximately 310 K).
Question 4
What is the boiling point of water on the Kelvin scale?
A. 273 K
B. 298 K
C. 310 K
D. 373 K
Answer: D. 373 K
Rationale: Water boils at 100°C. K = 100 + 273.15 = 373.15 K.
Question 5
What is the density of a substance with a mass of 50 g and a volume of 25 mL?
A. 1.0 g/mL
B. 2.0 g/mL
C. 0.5 g/mL
D. 4.0 g/mL
Answer: B. 2.0 g/mL
Rationale: Density = Mass / Volume = 50 g / 25 mL = 2.0 g/mL.
, Section 2: Atoms, Ions, and Periodic Table
Subatomic Particles
Particle Location Charge Mass
Proton Nucleus +1 1 amu
Neutron Nucleus 0 1 amu
Electron Outside nucleus -1 ~0 amu
Atomic Calculations
Calculation Formula
Atomic Number # of Protons
Mass Number Protons + Neutrons
# of Neutrons Mass Number - Atomic Number
# of Electrons (neutral) # of Protons
Isotopes
Atoms with the same number of protons (same element) but different numbers of
neutrons
Example: Carbon-12 and Carbon-14 both have 6 protons; Carbon-12 has 6 neutrons,
Carbon-14 has 8 neutrons
Electron Configuration
Electrons fill orbitals in order of increasing energy: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, etc.
