Questions on Density
Multiple-Choice Questions – Density (Chemistry)
1. What is the formula for density?
A) Density = mass × volume
B) Density = mass / volume
C) Density = volume / mass
D) Density = mass + volume
E) Density = volume - mass
2. Which units are commonly used for density in chemistry?
A) g/cm³ or g/mL
B) kg·m
C) m/s²
D) liters
E) moles
3. What is the density of an object with a mass of 50 g and a volume of 10 cm³?
A) 5 g/cm³
B) 500 g/cm³
C) 0.2 g/cm³
D) 60 g/cm³
E) 40 g/cm³
4. If the density of water is 1 g/mL, what is the volume of 250 g of water?
A) 250 mL
B) 25 mL
C) 0.25 mL
D) 2.5 mL
E) 2500 mL
5. Density is a ___ property because it does not depend on the amount of substance.
A) Extensive
B) Intensive
C) Variable
D) Absolute
E) Dependent
6. Which of the following substances will float on water?
A) Density = 1.5 g/cm³
B) Density = 1.0 g/cm³
C) Density = 0.8 g/cm³
D) Density = 2.0 g/cm³
E) Density = 1.2 g/cm³
7. How would the density of an object change if it is cut into smaller pieces?
A) Increase
B) Decrease
C) Remain the same
D) Double
E) Halve
8. What is the mass of an object with a density of 2.5 g/cm³ and a volume of 4 cm³?
A) 10 g
B) 6.5 g
C) 1.6 g
D) 0.625 g
E) 2.5 g
9. What is the volume of an object with mass 36 g and density 4.5 g/cm³?
A) 8 cm³
B) 40.5 cm³
C) 81 cm³
D) 0.125 cm³
E) 4 cm³
10. Which instrument is commonly used to measure the volume of irregular objects to calculate density?
A) Thermometer
B) Graduated cylinder
C) Balance
D) Spectrophotometer
E) Burette
11. What is the density of a liquid with mass 150 g and volume 200 mL?
A) 0.75 g/mL
B) 1.33 g/mL
C) 350 g/mL
D) 50 g/mL
E) 0.67 g/mL
12. If an object sinks in water, what can you infer about its density?
A) Density less than 1 g/cm³
B) Density equal to 1 g/cm³
C) Density greater than 1 g/cm³
D) Density zero
E) Density less than zero
13. How does temperature usually affect the density of a substance?
A) Density increases with temperature
B) Density decreases with temperature
C) Density remains constant
D) Density doubles
E) Density becomes zero
14. What is the density of a substance if 10 mL has a mass of 25 g?
A) 0.4 g/mL
B) 2.5 g/mL
C) 35 g/mL
D) 250 g/mL
E) 0.25 g/mL
15. Which of the following is an example of a correct density unit?
A) kg/cm³
B) g/L
C) m³/g
D) g/s
E) cm/g
16. When finding the density of a gas, what SI units are typically used?
A) g/mL
B) kg/m³
C) g/cm³
D) mol/L
E) m/s
17. Which of the following materials likely has the highest density?
A) Air
B) Wood
C) Gold
D) Oil
E) Ice
18. What happens to the density of water when it freezes into ice?
A) Increases
B) Decreases
C) Remains the same
D) Becomes zero
E) Doubles
19. A block of metal weighs 100 g and displaces 20 cm³ of water. What is the density of the metal?
A) 0.2 g/cm³
B) 2 g/cm³
C) 5 g/cm³
D) 20 g/cm³
E) 100 g/cm³
20. Why is density useful for identifying substances?
A) It varies greatly for the same material
B) It is the same for all substances
C) Each substance has a unique density
D) It depends on color
E) It depends on shape
Answer Key with Explanations
1. B) Density = mass / volume
Density is mass divided by volume.
2. A) g/cm³ or g/mL
Common units for density are grams per cubic centimeter or grams per milliliter.
3. A) 5 g/cm³
Density = 50 g ÷ 10 cm³ = 5 g/cm³.
4. A) 250 mL
Since density of water is 1 g/mL, volume = mass/density = 250 g / 1 g/mL = 250 mL.
5. B) Intensive
Density does not depend on amount, so it is an intensive property.
6. C) Density = 0.8 g/cm³
Objects with density less than water (1 g/cm³) float.
7. C) Remain the same
Density is independent of size or shape.
8. A) 10 g
Mass = density × volume = 2.5 g/cm³ × 4 cm³ = 10 g.
9. A) 8 cm³
Volume = mass / density = 36 g / 4.5 g/cm³ = 8 cm³.
10. B) Graduated cylinder
Used to measure volume of irregular solids via water displacement.
11. A) 0.75 g/mL
Density = 150 g / 200 mL = 0.75 g/mL.
12. C) Density greater than 1 g/cm³
Sinking means density higher than water.
13. B) Density decreases with temperature
Most substances expand and become less dense when heated.
14. B) 2.5 g/mL
Density = 25 g / 10 mL = 2.5 g/mL.
15. B) g/L
g/L is a valid density unit, especially for liquids and gases.
16. B) kg/m³
Density of gases often expressed in kilograms per cubic meter.
17. C) Gold
Gold is very dense compared to air, wood, oil, or ice.
18. B) Decreases
Ice is less dense than water, so it floats.
19. C) 5 g/cm³
Density = 100 g / 20 cm³ = 5 g/cm³.
20. C) Each substance has a unique density
Density is a characteristic property helpful in identification.
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