Difference Between Steam and Vapor

The key difference between steam and vapor is that steam is the gaseous state of water whereas vapor is the gaseous state of any substance.

We use the term “steam” as a common name to name water vapor specifically. The gaseous state of any other matter is “vapor”. Therefore, the use of the term is the key difference between steam and vapor. Other than that, there are a few more differences between steam and vapor that we are going to describe in this article.

CONTENTS

1. Overview and Key Difference
2. What is Steam
3. What is Vapor
4. Side by Side Comparison – Steam vs Vapor in Tabular Form
5. Summary

What is Steam?

Steam is simply, water vapor. Hence, the term steam describes the gaseous state of water. It forms when water boils. That means the steam exists at temperatures above 100◦C at standard pressure because water boils at this temperature. Typically, steam is invisible. However, if we refer to wet steam, it means visible mist or aerosol. The wet steam forms as a result of condensation of steam as water droplets.

The enthalpy of vaporization gives the amount of energy we need to produce steam from water at standard temperature and pressure. We can use this change in enthalpy as useful energy by converting into mechanical work using steam engines.

Followings are the uses of steam;

• In agriculture, it is useful for soil sterilization to increase soil health.
• In the kitchen, we can use it for steam cooking of vegetables.
• We can use it for heating buildings.
• Useful in ironing clothes as well.
• About 90% of the electricity we use is produced using steam energy.
• We can use steam under pressure in autoclaves.

What is Vapor?

Vapor is the gaseous state of any substance. But, this gaseous state exists at lower temperatures than the critical temperature of that substance. Hence, we can condense this vapor into a liquid form by increasing the pressure on the vapor while keeping the temperature as it is. Vapor differs from aerosol because aerosol contains tiny particles of liquid, solid, or both within a gas.

The boiling point of the substance determines the temperature at which the vapor forms and exists. Furthermore, vapor can co-exist with its liquid or solid phase in equilibrium with each other. More importantly, it is not essential to boil a substance in order to form a vapor; some substances are volatile, meaning those substances can turn into the gaseous state at the normal temperature and pressure conditions. When considering the uses of vapor, perfumes contain a substance that can easily vaporize to form vapors of perfume; water vapor can condense to form mist, mercury-vapor lamps can form the light, etc.

What is the Difference Between Steam and Vapor?

Steam is simply, water vapor whereas Vapor is the gaseous state of any substance. Thus, this is the main difference between steam and vapor. Moreover, another difference between steam and vapor is that the steam exists above 100◦C at standard pressure while the existence of vapor depends on the boiling point and volatility of the substance. When considering the visibility too we can identify a difference between steam and vapor. That is; the steam is typically invisible whereas the vapor of some substances is colorful. Above all, the vapor of flammable substances is flammable, but the steam is non-flammable.

The below infographic on difference between steam and vapor tabulates the differences discussed above.

Summary – Steam vs Vapor

Steam is simply, water vapor. Hence, the key difference between steam and vapor is that steam is the gaseous state of water whereas vapor is the gaseous state of any substance. Moreover, steam is typically invisible while the vapor of some substances is colorful.

Reference:

1. “What Is the Steam?” MEL Science. Available here 
2. “Vapor.” Wikipedia, Wikimedia Foundation, 2 Oct. 2018. Available here  

Image Courtesy:

1.”Kochendes wasser02″By user:Markus Schweiss – Own work, (CC BY-SA 3.0) via Commons Wikimedia  
2.”IodoAtomico”By Matias Molnar – Laboratorio Quimica Inorganica II – UBA, Argentina, (CC BY-SA 3.0) via Commons Wikimedia