A scientist is studying rocks found within layers of Earth. She finds a rock with a mass of 72 grams and a volume of 24 cm3.

Question

The table shows the average densities of rocks that are commonly found in the area where the scientist found the rock. Densities are rounded to the nearest tenth.

Average Densities of Rocks g/cm3
Shale 2.0
Quartzite 3.0
Sandstone 2.5
Marble 2.7
Limestone 1.2

According to the data, what type of rock did the scientist find? (1 point)

Quartzite
Limestone
Sandstone
Shale

Answer 1

To determine the type of rock the scientist found, we first need to calculate its density. Density is calculated using the formula:

\[ \text{Density} = \frac{\text{Mass}}{\text{Volume}} \]

Given the mass of the rock is 72 grams and the volume is 24 cm³, we can calculate its density as follows:

\[ \text{Density} = \frac{72 \text{ g}}{24 \text{ cm}^3} = 3.0 \text{ g/cm}^3 \]

Now we can compare this density with the average densities of the rocks listed in the table:

• Shale: 2.0 g/cm³
• Quartzite: 3.0 g/cm³
• Sandstone: 2.5 g/cm³
• Marble: 2.7 g/cm³
• Limestone: 1.2 g/cm³

Since the calculated density of the rock is 3.0 g/cm³, the type of rock the scientist found is Quartzite.