Calculating the Maximum Safe Volume of Ethanol in a Confined Space

[Shannon hunt]

Hello
The lower flammability point of ethanol is 3.5% v/v. How can I work out the max volume of ethanol in a specified space to be lower than the flammability point
Eg
If I have a 100l vessel 3.5% will be 3.5l of vapour in that 100l vessel that will make it ignitable - how can I convert 3.5 l of ethanol vapour back to the volume of ethanol as liquid(pressure and t at ambient at this point)
Thank u

 

[nasu]

You can have an estimate by assuming the vapors behave like an ideal gas.
In normal conditions, you can find the number of moles in 3.5 L of vapors like
N=3.5/22.4
Then multiply by molar mass o get the mass of ethanol in these 3.5 L.
And knowing the mass and density of liquid you can find the volume of liquid.