December 23, 2024, 10:57:39 AM
Forum Rules: Read This Before Posting


Topic: problems with Hess's Law  (Read 4466 times)

0 Members and 1 Guest are viewing this topic.

Offline kenny122

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
problems with Hess's Law
« on: November 11, 2007, 03:50:39 PM »
i have an assignment, and one of the questions is:

Reaction 3-The molar heat of formation of H2O (l) is -285.8 kJ/mol

from this reaction, calculate the heat of reaction.

i know i should know how to do it, but it is confusing the heck out of me. thanks.

Offline LQ43

  • Chemist
  • Full Member
  • *
  • Posts: 250
  • Mole Snacks: +32/-9
  • Gender: Female
Re: problems with Hess's Law
« Reply #1 on: November 11, 2007, 04:35:32 PM »
there seems to be alot of information missing,

what is the reaction?

Offline kenny122

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
Re: problems with Hess's Law
« Reply #2 on: November 11, 2007, 04:44:28 PM »
well, i'm left to figure that out too. i am pretty sure its 2H2+O2=2H20

Offline LQ43

  • Chemist
  • Full Member
  • *
  • Posts: 250
  • Mole Snacks: +32/-9
  • Gender: Female
Re: problems with Hess's Law
« Reply #3 on: November 11, 2007, 04:56:27 PM »
okay, well the molar heat of formation is -285.8 kJ/mol

that means 1 mol of H2O gives this heat

for your equan which gives 2 moles, how much heat?

Offline kenny122

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
Re: problems with Hess's Law
« Reply #4 on: November 11, 2007, 05:18:08 PM »
ohhh...lol. -571.6. thanks so much!!

Sponsored Links