Chemical Forums

Please login or register.

Login with username, password and session length

Sponsored links

Pages: [1]   Go Down

Author Topic: Enthalpy of MgCl2  (Read 5620 times)

0 Members and 1 Guest are viewing this topic.


  • Regular Member
  • ***
  • Mole Snacks: +1/-0
  • Offline Offline
  • Posts: 36
Enthalpy of MgCl2
« on: November 24, 2011, 03:46:26 AM »

Greetings all. I had a lab from which I measured 6822.8 joules released by the reaction of Mg+2HCl->MgCl2+H2. The limiting reagent is Mg. I used 1.68E-2 moles (.0168 moles) of Mg meaning there is the same number of moles of MgCl2. Dividing 6822.8 Joules by .0168 to get joules per mole (and kj per mol) gives -406.1kj/mol.
Problem is is that apparently the heat of formation of MgCl2 is -641.8kj/mol.
Any suggestion as to where I went wrong? thanks


  • Full Member
  • ****
  • Mole Snacks: +41/-58
  • Offline Offline
  • Gender: Female
  • Posts: 703
  • Online Chemistry and Organic Chemistry tutor
    • Online Chemistry Tutor
Re: Enthalpy of MgCl2
« Reply #1 on: November 24, 2011, 03:58:43 AM »

here you have calculated the heat of the reaction

however heat of formation is for Mg(s) + Cl2(g) ---> MgCl2(s)
there is a difference in the reactions

Pages: [1]   Go Up

Mitch Andre Garcia's Chemical Forums 2003-Present.

Page created in 0.061 seconds with 23 queries.