December 10, 2024, 04:32:54 PM
Forum Rules: Read This Before Posting


Topic: Problem of the week - 30/07/2012  (Read 23712 times)

0 Members and 1 Guest are viewing this topic.

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27884
  • Mole Snacks: +1815/-412
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Problem of the week - 30/07/2012
« Reply #15 on: August 14, 2012, 04:17:14 AM »
You can assume pressure around 1 atm.

ok so molar mass gas = 201.79 g/mol

No. But I am not able to reproduce the correct answer either  :'(, and as I calculated it in the Dalmatino bar using a napkin, I have no notes to consult.

Trick is, 10.2 g is not a weight of the added gas - it is the increase of the weight, so you should take buoyancy into account. As the volume is 1.22 L, and the air density is around 1.2 g/L, buoyancy is around 1.22*1.2=1.46 g - so the weight of the gas is around 10.2+1.4=11.6 g. That gives molar mass of around 230.

It should be 15.05-1.22*1.2=13.6 g, I am changing the wording of the original question. Sorry about that.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline Ann1234

  • Regular Member
  • ***
  • Posts: 63
  • Mole Snacks: +4/-0
  • Gender: Female
Re: Problem of the week - 30/07/2012
« Reply #16 on: August 14, 2012, 12:31:26 PM »
You can assume pressure around 1 atm.

ok so molar mass gas = 201.79 g/mol

No. But I am not able to reproduce the correct answer either  :'(, and as I calculated it in the Dalmatino bar using a napkin, I have no notes to consult.

Trick is, 10.2 g is not a weight of the added gas - it is the increase of the weight, so you should take buoyancy into account. As the volume is 1.22 L, and the air density is around 1.2 g/L, buoyancy is around 1.22*1.2=1.46 g - so the weight of the gas is around 10.2+1.4=11.6 g. That gives molar mass of around 230.

It should be 15.05-1.22*1.2=13.6 g, I am changing the wording of the original question. Sorry about that.


no worries  :)


Sponsored Links