Does the Density of a Volatile Liquid Change with Evaporation?

Volatile ingredients in perfume cause the fragrant mist to evaporate quickly.
••• Jupiterimages/ Images

When some people hear the phrase "volatile liquid," they might think that the liquid is explosive or dangerous. However, the defining characteristic that makes a liquid like alcohol volatile is that it has a low boiling point, which also means it evaporates easily at room temperature. You might think that because a liquid evaporates, the loss of molecules causes the remaining molecules to become less tightly packed, and therefore less dense, but it doesn't.

A Relative Loss

You calculate density by dividing a substance's mass by its volume. For example, a sample with a mass of 500 kilograms and a volume of 500 cubic meters will have a density of 1 kilogram/cubic meter: 500 / 500 = 1. When that liquid evaporates, it loses molecules from its surface, which causes both its mass and volume to decrease proportionally, molecule by molecule. If half of that sample evaporated, its mass would then be 250 kilograms and its volume would have also lowered to 250 cubic meters. Its density would still be 1 kilogram per cubic meter: 250 / 250 = 1.

Related Articles

How to Calculate Solubilities
What Is the Difference Between Mass, Weight and Volume?
Four Things That Affect Rate of Diffusion
Science Project: The Effects of Temperature on Liquids
How to Convert Grams to Cups
How to Convert Specific Gravity in Weight
How to Convert ATM Pressure to Celsius
What Type of Reaction Is Occurring When Sulfuric Acid...
How to Convert Density to Grams
Density to Molarity Conversion
Why Do Hydrates Change Color When Heated?
Temperature Effects on Density
Does Viscosity Increase With the Size of the Molecule?
Why Does Sugar Melt Ice?
The Effects of Heating H2O2 and Stability
How Do pH Buffers Work?
Volume Vs. Mass Density
Conversion of LBM to Gallons
What Are Five Properties of Gases?
How to Calculate Volume From Centimeters

Dont Go!

We Have More Great Sciencing Articles!