Question

Difficulty: HardProperties of Matter

A rectangular glass container with internal base dimensions of 5 cm5\text{ cm} by 4 cm4\text{ cm} contains water. A solid mineral specimen with a mass of 130 g130\text{ g} is completely submerged into the water, causing the water level to rise by 2.5 cm2.5\text{ cm} without spilling. What is the density of the mineral specimen in g/cm3\text{g/cm}^3?

Answer: 2.6 g/cm^3

Answer

The density of the mineral specimen is 2.6 g/cm32.6\text{ g/cm}^3.
Density is calculated by dividing mass by volume (ρ=mV\rho = \frac{m}{V}). The water displacement method reveals the object's volume: Volume=length×width×Δh=5 cm×4 cm×2.5 cm=50 cm3\text{Volume} = \text{length} \times \text{width} \times \Delta h = 5\text{ cm} \times 4\text{ cm} \times 2.5\text{ cm} = 50\text{ cm}^3. Dividing the given mass of 130 g130\text{ g} by the displaced volume of 50 cm350\text{ cm}^3 yields exactly 2.6 g/cm32.6\text{ g/cm}^3.

Step-by-Step Solution

1
Calculate the volume of the displaced water inside the rectangular container.
V=5 cm×4 cm×2.5 cm=50 cm3V = 5\text{ cm} \times 4\text{ cm} \times 2.5\text{ cm} = 50\text{ cm}^3
The volume of fluid pushed upward corresponds to the area of the base multiplied by the change in water height.
2
Equate the volume of the submerged solid to the displaced fluid volume.
Vspecimen=50 cm3V_{\text{specimen}} = 50\text{ cm}^3
By the principle of fluid displacement, a completely submerged solid displaces a volume of fluid exactly equal to its own physical volume.
3
Calculate the density of the specimen using the mass-to-volume ratio.
ρ=mV=130 g50 cm3=2.6 g/cm3\rho = \frac{m}{V} = \frac{130\text{ g}}{50\text{ cm}^3} = 2.6\text{ g/cm}^3
Density is an intensive physical property defined as mass per unit volume.

Key Concept

Density is an intensive physical property of matter defined as mass per unit volume (ρ=m/V\rho = m/V), determinable for irregular or submerged solids via fluid displacement.
Estimated Time:1m 30s
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