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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: bfl27 on January 16, 2020, 12:00:09 PM

Title: Percent by Volume of/in Air
Post by: bfl27 on January 16, 2020, 12:00:09 PM

Hi,

I was hoping someone could clear up some confusion I'm having regarding balance a reaction at the concentration of the Lower Flammability limit of Pentane Fuel reacting in Air (assuming 79% N2 and 21% O2).

I'm confused on the meaning of 1.5% volume pentane in air.  I attached an image of two ways, and can't figure out which is correct.

Thanks for any help.

Title: Re: Percent by Volume of/in Air
Post by: MNIO on January 16, 2020, 12:33:32 PM

so your question is essentially...

does 1.5% by volume pentane mean
  1.5L pentane / 100 liters air
or
  1.5L pentane / 100 liters total vapor = 1.5L pentane / (100 L pentane + N2 + O2 combined)

it's the later of the two.
  1.5% pentane = 1.5L pentane + 98.5L air