Which of the following correctly describes how to calculate the density of air?

• A. Add the mass of air to its volume.
• B. Multiply the mass of air by its volume.
• C. Subtract the volume of air from its mass.
• D. Divide the mass of air by its volume.

Answer: (D)

Verified step by step guidance

1. Recall the definition of density, which is a measure of how much mass is contained in a given volume. The formula for density is given by \(\text{density} = \frac{\text{mass}}{\text{volume}}\).
2. Identify the quantities involved: the mass of air (usually in grams or kilograms) and the volume of air (usually in liters or cubic meters).
3. To find the density of air, you need to divide the mass of the air by the volume it occupies, which means performing the calculation \(\text{density} = \frac{\text{mass of air}}{\text{volume of air}}\).
4. Understand why other operations are incorrect: adding mass and volume is not meaningful because they have different units; multiplying mass by volume does not give a density; subtracting volume from mass is also not meaningful.
5. Therefore, the correct method to calculate the density of air is to divide the mass of air by its volume.