WGU D425 INTRO TO CHEMISTRY
OBJECTIVE ASSESSMENT 2026 | VERIFIED
QUESTIONS & ANSWERS | COMPREHENSIVE
EXAM PREP
WGU D425 INTRO TO CHEMISTRY OBJECTIVE ASSESSMENT 2026 | VERIFIED
QUESTIONS & ANSWERS | COMPREHENSIVE EXAM PREP
DOCUMENT OVERVIEW
• This comprehensive exam preparation material contains 300 verified questions
covering all major chemistry topics tested in WGU D425, designed to simulate real
assessment conditions and build mastery across fundamental to intermediate
concepts.
• Use this guide to identify knowledge gaps, practice time management, strengthen
weak areas through detailed rationale explanations, and build confidence before
taking the official assessment.
QUESTIONS 1-10: MATTER, MEASUREMENT & BASIC CONCEPTS
1. Which of the following is a physical property?
A) Flammability of paper
B) Rusting of iron
C) Melting point of ice
D) Combustion of gasoline
E) Decomposition of water
CORRECT ANSWER: C) Melting point of ice
RATIONALE: Physical properties are characteristics of matter that can be observed
or measured without changing the substance's chemical identity. Melting point is a
,physical property because ice can melt and refreeze without becoming a different
substance. Flammability, rusting, combustion, and decomposition are all chemical
properties because they involve changes in the substance's chemical composition
and produce new materials.
2. What is the SI unit for mass?
A) Pound
B) Kilogram
C) Newton
D) Gram
E) Ounce
CORRECT ANSWER: B) Kilogram
RATIONALE: The kilogram (kg) is the SI (International System of Units) base unit for
mass. While grams are also metric units and commonly used in chemistry, the
kilogram is the official SI standard. Pounds and ounces are imperial units, and the
newton is a unit of force, not mass.
3. How many significant figures are in the measurement 0.00450 m?
A) 2 significant figures
B) 3 significant figures
C) 4 significant figures
D) 5 significant figures
E) 6 significant figures
CORRECT ANSWER: B) 3 significant figures
,RATIONALE: Leading zeros (0.00) are not significant; they only serve as
placeholders. The significant figures are 4, 5, and the trailing zero after 5. Therefore,
0.00450 has 3 significant figures. Trailing zeros after a decimal point are significant.
4. What is the result of 15.2 × 3.1 expressed with the correct number of
significant figures?
A) 47.12
B) 47.1
C) 47
D) 50
E) 47.120
CORRECT ANSWER: C) 47
RATIONALE: In multiplication, the answer should have the same number of
significant figures as the measurement with the fewest significant figures. 15.2 has
3 significant figures, while 3.1 has 2 significant figures. Therefore, the answer must
be rounded to 2 significant figures: 47 (not 47.12).
5. Which of the following is an example of a pure substance?
A) Salt water
B) Air
C) Distilled water
D) Soil
E) Milk
CORRECT ANSWER: C) Distilled water
RATIONALE: A pure substance has a constant composition and fixed physical
properties. Distilled water is pure H₂O with a definite composition. Salt water, air,
, soil, and milk are all mixtures containing two or more substances that can vary in
composition and are not pure substances.
6. The temperature 25°C is equivalent to which Kelvin temperature?
A) 248.15 K
B) 273.15 K
C) 298.15 K
D) 312.15 K
E) 325.15 K
CORRECT ANSWER: C) 298.15 K
RATIONALE: The conversion formula from Celsius to Kelvin is K = °C + 273.15.
Therefore, 25°C + 273.15 = 298.15 K. This is an important conversion used
frequently in chemistry calculations, especially in gas law problems.
7. What is the density of a substance that has a mass of 45 g and a volume of
15 mL?
A) 0.33 g/mL
B) 2.0 g/mL
C) 3.0 g/mL
D) 30 g/mL
E) 60 g/mL
CORRECT ANSWER: C) 3.0 g/mL
RATIONALE: Density is calculated using the formula: Density = Mass/Volume.
Therefore, Density = 45 g ÷ 15 mL = 3.0 g/mL. This is a fundamental calculation in
chemistry for identifying substances and solving various problems.
OBJECTIVE ASSESSMENT 2026 | VERIFIED
QUESTIONS & ANSWERS | COMPREHENSIVE
EXAM PREP
WGU D425 INTRO TO CHEMISTRY OBJECTIVE ASSESSMENT 2026 | VERIFIED
QUESTIONS & ANSWERS | COMPREHENSIVE EXAM PREP
DOCUMENT OVERVIEW
• This comprehensive exam preparation material contains 300 verified questions
covering all major chemistry topics tested in WGU D425, designed to simulate real
assessment conditions and build mastery across fundamental to intermediate
concepts.
• Use this guide to identify knowledge gaps, practice time management, strengthen
weak areas through detailed rationale explanations, and build confidence before
taking the official assessment.
QUESTIONS 1-10: MATTER, MEASUREMENT & BASIC CONCEPTS
1. Which of the following is a physical property?
A) Flammability of paper
B) Rusting of iron
C) Melting point of ice
D) Combustion of gasoline
E) Decomposition of water
CORRECT ANSWER: C) Melting point of ice
RATIONALE: Physical properties are characteristics of matter that can be observed
or measured without changing the substance's chemical identity. Melting point is a
,physical property because ice can melt and refreeze without becoming a different
substance. Flammability, rusting, combustion, and decomposition are all chemical
properties because they involve changes in the substance's chemical composition
and produce new materials.
2. What is the SI unit for mass?
A) Pound
B) Kilogram
C) Newton
D) Gram
E) Ounce
CORRECT ANSWER: B) Kilogram
RATIONALE: The kilogram (kg) is the SI (International System of Units) base unit for
mass. While grams are also metric units and commonly used in chemistry, the
kilogram is the official SI standard. Pounds and ounces are imperial units, and the
newton is a unit of force, not mass.
3. How many significant figures are in the measurement 0.00450 m?
A) 2 significant figures
B) 3 significant figures
C) 4 significant figures
D) 5 significant figures
E) 6 significant figures
CORRECT ANSWER: B) 3 significant figures
,RATIONALE: Leading zeros (0.00) are not significant; they only serve as
placeholders. The significant figures are 4, 5, and the trailing zero after 5. Therefore,
0.00450 has 3 significant figures. Trailing zeros after a decimal point are significant.
4. What is the result of 15.2 × 3.1 expressed with the correct number of
significant figures?
A) 47.12
B) 47.1
C) 47
D) 50
E) 47.120
CORRECT ANSWER: C) 47
RATIONALE: In multiplication, the answer should have the same number of
significant figures as the measurement with the fewest significant figures. 15.2 has
3 significant figures, while 3.1 has 2 significant figures. Therefore, the answer must
be rounded to 2 significant figures: 47 (not 47.12).
5. Which of the following is an example of a pure substance?
A) Salt water
B) Air
C) Distilled water
D) Soil
E) Milk
CORRECT ANSWER: C) Distilled water
RATIONALE: A pure substance has a constant composition and fixed physical
properties. Distilled water is pure H₂O with a definite composition. Salt water, air,
, soil, and milk are all mixtures containing two or more substances that can vary in
composition and are not pure substances.
6. The temperature 25°C is equivalent to which Kelvin temperature?
A) 248.15 K
B) 273.15 K
C) 298.15 K
D) 312.15 K
E) 325.15 K
CORRECT ANSWER: C) 298.15 K
RATIONALE: The conversion formula from Celsius to Kelvin is K = °C + 273.15.
Therefore, 25°C + 273.15 = 298.15 K. This is an important conversion used
frequently in chemistry calculations, especially in gas law problems.
7. What is the density of a substance that has a mass of 45 g and a volume of
15 mL?
A) 0.33 g/mL
B) 2.0 g/mL
C) 3.0 g/mL
D) 30 g/mL
E) 60 g/mL
CORRECT ANSWER: C) 3.0 g/mL
RATIONALE: Density is calculated using the formula: Density = Mass/Volume.
Therefore, Density = 45 g ÷ 15 mL = 3.0 g/mL. This is a fundamental calculation in
chemistry for identifying substances and solving various problems.
