December 28, 2024, 08:45:30 PM
Forum Rules: Read This Before Posting


Topic: % by mass???  (Read 5162 times)

0 Members and 1 Guest are viewing this topic.

Offline cronosking

  • Regular Member
  • ***
  • Posts: 9
  • Mole Snacks: +0/-0
% by mass???
« on: October 07, 2007, 11:19:47 PM »
How can I calculate percent by mass of a x subtance???

Thanks!!!

Offline DevaDevil

  • Chemist
  • Full Member
  • *
  • Posts: 690
  • Mole Snacks: +55/-9
  • Gender: Male
  • postdoc at ANL
Re: % by mass???
« Reply #1 on: October 08, 2007, 12:36:55 PM »
I assume you mean mass% of a substance in a mixed compound.

That is quite straightforward: {mass of the substance / mass of the compound} * 100%


If this is not what you mean, you need to formulate your question more clearly

Offline cronosking

  • Regular Member
  • ***
  • Posts: 9
  • Mole Snacks: +0/-0
Re: % by mass???
« Reply #2 on: October 08, 2007, 07:10:20 PM »
my bad

i am doing a acid-base titration lab report and the question says "use your data from this experiment to calculate the % by mass of ethanoic acid present in commertial, undiluted vinegar."

We used KHP, NaOH, and vinegar, found the nomality for NaOH and vinegar, got the mass of KHP, etc...

Offline Yggdrasil

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 3215
  • Mole Snacks: +485/-21
  • Gender: Male
  • Physical Biochemist
Re: % by mass???
« Reply #3 on: October 08, 2007, 07:56:25 PM »
% mass is basically a measure of concentration.  It is the mass of your compound per 100g of solution (so for example, 1g of acetic acid in 100g of solution is a 1% solution).  For dilute aqueous solutions, this is approximately equal to the weight of your compound per 100mL of solution (since for pure water 1g = 1mL).

Offline cronosking

  • Regular Member
  • ***
  • Posts: 9
  • Mole Snacks: +0/-0
Re: % by mass???
« Reply #4 on: October 08, 2007, 08:44:47 PM »
got it thanks

Sponsored Links