# COMMUNITY : FORUMS : SCIENCE

## What's the gas expansion ratio for ethanol?

At normal atmospheric pressure. Don't need too precise a figure, nearest 50 will do.

Surprisingly difficult information to find...

lemonie7 years ago
What do you mean? Vapour pressure or volume gas per ml liquid?
I'll assume you want "how much gas do I get at the boiling point?".
Molar volume of a gas at 25oC is ~ 25 L, which is 46g, or ~58ml.

Treating it as an ideal gas, V=RT/P
At boiling point and atmospheric pressure V ~29 Litres gas for 58ml liquid, or about 500x liquid volume.

L

SolarFlower_org (author)  lemonie7 years ago
That is what I was after, thanks.
7 years ago
Hooray!

The idea gas equation can be found here (of many places), I guess you'll be wanting pressures at some point?
en.wikipedia.org/wiki/Molar_volume

L
SolarFlower_org (author)  lemonie7 years ago
I had a look at that, but as is my way now of outsourcing all my thinking to the internet: wolfram alpha.

Pressures shouldn't be an issue.