What is expansion ratio?

• A. The density ratio of gas to liquid
• B. The volume of a substance in liquid form compared to its gas form
• C. The mass ratio of two liquids
• D. The pressure ratio of gas at two temps

Answer: (C)

Expansion ratio describes how much volume increases when a substance changes from liquid to gas. It compares the gas volume produced to the original liquid volume, showing how many liters of vapor come from one liter of liquid. This is important because liquids can be compact in storage, but their vapors can occupy vastly more space, affecting containment, safety, and handling. The correct way to think about it is the volume of gas formed relative to the liquid volume; the other ideas—density ratio, mass ratio, or pressure changes—are different concepts. For example, if one liter of liquid yields hundreds of liters of gas, the expansion ratio would be that large gas volume per liter of liquid.