Chemical Forums

Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: SheffieldWednesday4ever on September 25, 2009, 07:14:17 PM

Title: Compound purity
Post by: SheffieldWednesday4ever on September 25, 2009, 07:14:17 PM

Hey everyone,

I had a solution of Acetic anhydride marked with 99.5% in the lab. I was supposed to find out the number of moles and weight. So I found out the density from Sigma-Aldrich (1.08g/1ml). I used 2ml so i multiplied 2mlX1.08 which gave 2.16 grams. But because it said 99.5%, should I multiply the 2.16 grams with 0.995?

I appreciate any help.
Thanks for reading.

Title: Re: Compound purity
Post by: Borek on September 25, 2009, 07:38:51 PM

Yes, although in this case it doesn't matter - as long as you have not measured 2.00 mL, volume error is much larger than errors due to the 0.5% of impurities.