Does the Density of a Volatile Liquid Change with Evaporation?

Volatile ingredients in perfume cause the fragrant mist to evaporate quickly.
••• Jupiterimages/Photos.com/Getty 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

Science Project: The Effects of Temperature on Liquids
Does Viscosity Increase With the Size of the Molecule?
Four Things That Affect Rate of Diffusion
Density to Molarity Conversion
The Effects of Heating H2O2 and Stability
What Happens After Water Vapor Condenses?
How to Convert ATM Pressure to Celsius
How to Calculate Concentration From Density
Why Do Hydrates Change Color When Heated?
If Something Fizzes Does It Mean That It Is Giving...
Does Kinetic Energy Increase in a Drink When Ice Melts?
What Are Five Properties of Gases?
How Does Changing the Temperature Affect the Viscosity...
Temperature Effects on Density
How to Convert Density to Grams
How to Calculate Solubilities
How Temperature Affects the Stretch of a Rubber Band
How Does Humidity Affect Speed of Sound?
Conversion of LBM to Gallons
Explanation of the Difference Between Viscosity & Buoyancy

Dont Go!

We Have More Great Sciencing Articles!