1
WGU D425 INTRODUCTION TO CHEMISTRY
OBJECTIVE ASSESSMENT STUDY GUIDE |
LATEST UPDATE 2025/2026 | PRACTICE
QUESTIONS AND ANSWERS | EXAM REVIEW |
100% CORRECT ANSWERS | VERIFIED
SOLUTIONS
This comprehensive practice examination is designed for students preparing for
the WGU D425 Introduction to Chemistry Objective Assessment. It serves as a
complete study guide and exam review, reflecting the latest update for 2025/2026.
The questions are meticulously crafted to mirror the difficulty, scenario-based
style, and scope of the assessment, covering all essential domains including
scientific method and measurement, atomic structure, the periodic table, chemical
bonding, chemical reactions, stoichiometry, solutions, acids and bases, gases,
thermochemistry, and nuclear chemistry. By engaging with these practice
questions and answers, candidates can assess readiness, identify knowledge gaps,
and reinforce critical chemistry concepts. The detailed rationales provide verified
solutions, ensuring deep comprehension and enhancing preparation for this
competency-based assessment.
Table of Contents
1. Scientific Method and Measurement
2. Matter and Its Properties
3. Atomic Structure and the Periodic Table
4. Chemical Bonding and Molecular Geometry
5. Chemical Reactions and Stoichiometry
6. Solutions and Their Behavior
7. Acids, Bases, and pH
8. Gases and Gas Laws
9. Thermochemistry and Energy
10. Nuclear Chemistry
, 2
Question 1: Which of the following best defines a scientific hypothesis?
A) A proven fact
B) A testable explanation for an observation
C) A final conclusion
D) An unchangeable law
Correct Answer: B
A hypothesis is a testable, tentative explanation for a phenomenon. It is not proven
(Option A), not final (Option C), and not unchangeable (Option D). Hypotheses
are supported or refuted through experimentation.
Question 2: What is the SI base unit for length?
A) Meter
B) Liter
C) Gram
D) Second
Correct Answer: A
The meter is the SI base unit for length. The liter is volume, the gram is mass, and
the second is time.
Question 3: How many significant figures are in the measurement 0.004560 m?
A) 3
B) 4
C) 5
D) 7
, 3
Correct Answer: B
Significant figures include non-zero digits, zeros between non-zero digits, and
trailing zeros after a decimal. In 0.004560, the digits 4, 5, 6, and the trailing 0 are
significant, giving 4 significant figures.
Question 4: Convert 250 centimeters to meters.
A) 0.25 m
B) 2.5 m
C) 25 m
D) 2500 m
Correct Answer: B
There are 100 cm in 1 m, so 250 cm ÷ 100 = 2.5 m.
Question 5: Which of the following is a chemical property?
A) Density
B) Melting point
C) Flammability
D) Color
Correct Answer: C
Flammability describes how a substance reacts to form new substances, which is a
chemical property. Density, melting point, and color are physical properties.
Question 6: Which state of matter has a definite volume but no definite shape?
, 4
A) Solid
B) Liquid
C) Gas
D) Plasma
Correct Answer: B
A liquid has definite volume but takes the shape of its container. A solid has
definite shape and volume. A gas has neither. Plasma is ionized gas.
Question 7: What is the phase change from solid directly to gas called?
A) Melting
B) Sublimation
C) Condensation
D) Freezing
Correct Answer: B
Sublimation is solid to gas without passing through liquid. Melting is solid to
liquid. Condensation is gas to liquid. Freezing is liquid to solid.
Question 8: Which subatomic particle has a positive charge?
A) Electron
B) Neutron
C) Proton
D) Photon
WGU D425 INTRODUCTION TO CHEMISTRY
OBJECTIVE ASSESSMENT STUDY GUIDE |
LATEST UPDATE 2025/2026 | PRACTICE
QUESTIONS AND ANSWERS | EXAM REVIEW |
100% CORRECT ANSWERS | VERIFIED
SOLUTIONS
This comprehensive practice examination is designed for students preparing for
the WGU D425 Introduction to Chemistry Objective Assessment. It serves as a
complete study guide and exam review, reflecting the latest update for 2025/2026.
The questions are meticulously crafted to mirror the difficulty, scenario-based
style, and scope of the assessment, covering all essential domains including
scientific method and measurement, atomic structure, the periodic table, chemical
bonding, chemical reactions, stoichiometry, solutions, acids and bases, gases,
thermochemistry, and nuclear chemistry. By engaging with these practice
questions and answers, candidates can assess readiness, identify knowledge gaps,
and reinforce critical chemistry concepts. The detailed rationales provide verified
solutions, ensuring deep comprehension and enhancing preparation for this
competency-based assessment.
Table of Contents
1. Scientific Method and Measurement
2. Matter and Its Properties
3. Atomic Structure and the Periodic Table
4. Chemical Bonding and Molecular Geometry
5. Chemical Reactions and Stoichiometry
6. Solutions and Their Behavior
7. Acids, Bases, and pH
8. Gases and Gas Laws
9. Thermochemistry and Energy
10. Nuclear Chemistry
, 2
Question 1: Which of the following best defines a scientific hypothesis?
A) A proven fact
B) A testable explanation for an observation
C) A final conclusion
D) An unchangeable law
Correct Answer: B
A hypothesis is a testable, tentative explanation for a phenomenon. It is not proven
(Option A), not final (Option C), and not unchangeable (Option D). Hypotheses
are supported or refuted through experimentation.
Question 2: What is the SI base unit for length?
A) Meter
B) Liter
C) Gram
D) Second
Correct Answer: A
The meter is the SI base unit for length. The liter is volume, the gram is mass, and
the second is time.
Question 3: How many significant figures are in the measurement 0.004560 m?
A) 3
B) 4
C) 5
D) 7
, 3
Correct Answer: B
Significant figures include non-zero digits, zeros between non-zero digits, and
trailing zeros after a decimal. In 0.004560, the digits 4, 5, 6, and the trailing 0 are
significant, giving 4 significant figures.
Question 4: Convert 250 centimeters to meters.
A) 0.25 m
B) 2.5 m
C) 25 m
D) 2500 m
Correct Answer: B
There are 100 cm in 1 m, so 250 cm ÷ 100 = 2.5 m.
Question 5: Which of the following is a chemical property?
A) Density
B) Melting point
C) Flammability
D) Color
Correct Answer: C
Flammability describes how a substance reacts to form new substances, which is a
chemical property. Density, melting point, and color are physical properties.
Question 6: Which state of matter has a definite volume but no definite shape?
, 4
A) Solid
B) Liquid
C) Gas
D) Plasma
Correct Answer: B
A liquid has definite volume but takes the shape of its container. A solid has
definite shape and volume. A gas has neither. Plasma is ionized gas.
Question 7: What is the phase change from solid directly to gas called?
A) Melting
B) Sublimation
C) Condensation
D) Freezing
Correct Answer: B
Sublimation is solid to gas without passing through liquid. Melting is solid to
liquid. Condensation is gas to liquid. Freezing is liquid to solid.
Question 8: Which subatomic particle has a positive charge?
A) Electron
B) Neutron
C) Proton
D) Photon
