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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: zeshkani on April 22, 2008, 12:12:17 AM

Title: quick question
Post by: zeshkani on April 22, 2008, 12:12:17 AM
i just have a quick question, this might be so silly  ;D

it says calculated the volume needed from the percents and densities for an FTIR experiment
how much ehtanol is needed to make a 20mL of a 0.5136[M] Ethanol solution whose percent purity is 100%

would this just be take the [M] x Volume(0.02L) = Moles x MW(46.07g/mol)/Density(0.7904g/mL) which will give me volume of ethanol needed then just dilute to 20mL right ??
Title: Re: quick question
Post by: Borek on April 22, 2008, 03:20:25 AM
20mL of a 0.5136[M] Ethanol solution whose percent purity is 100%

Something is wrong with the question - 0.5136M ethanol is not 100% pure.

Could be you are right.
Title: Re: quick question
Post by: JGK on April 22, 2008, 01:18:16 PM
20mL of a 0.5136[M] Ethanol solution whose percent purity is 100%

Something is wrong with the question - 0.5136M ethanol is not 100% pure.

Could be you are right.

I think the question should be more correctly phrased as follows:

"What volume of 100% pure ethanol is needed to make a 20mL of a 0.5136[M] Ethanol solution."

Title: Re: quick question
Post by: zeshkani on April 22, 2008, 01:20:49 PM
yeah your right, sorry for the confusing question.

so yeah we need to figure out how much 100% ethanol to use to make a 0.5136M Ethanol Solution
but is the way i described it right in my first post or em i totally off
Title: Re: quick question
Post by: Borek on April 22, 2008, 01:31:30 PM
OK, although you abused equal sign :)