Calculating enthalpy

Chemistry and homework help forum.

Organic Chemistry, Analytical Chemistry, Biochemistry, Physical Chemistry, Computational Chemistry, Theoretical Chemistry, High School Chemistry, Colledge Chemistry and University Chemistry Forum.

Share your chemistry ideas, discuss chemical problems, ask for help with scientific chemistry questions, inspire others by your chemistry vision!

Please feel free to start a scientific chemistry discussion here!

Discuss chemistry homework problems with experts!

Ask for help with chemical questions and help others with your chemistry knowledge!

Moderators: expert, ChenBeier, Xen

Post Reply
vasilivv
Newbie
Newbie
Posts: 1
Joined: Mon Nov 22, 2021 8:22 am

Calculating enthalpy

Post by vasilivv »

Hi!
I'm going to translate a task from my native language to English, so sorry in advance if there are some mistakes and terms are off.
I got this equation - 2H2 + O2 -> 2H2O and I need to calculate the enthalpy.

In this reaction, a mixture of H2 and O2 is 180g (g is equally distributed.)
I know that I need to calculate the moles to be able to get the enthalpy, but I'm not sure how to do so. I have tried to come up with ideas, but nothing has come to my mind.
User avatar
ChenBeier
Distinguished Member
Distinguished Member
Posts: 983
Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

Re: Calculating enthalpy

Post by ChenBeier »

You have 90 g H2 and 90 g O2 correct.
That mean you have 90/2 = 45 mol H2 and 90/32 = 2,81 mol O2
So you can only do the double what means 5,625 mol H2 bring in reaction
You will get the same amount of water, what is x 18 g/ mol = 101,25 g. The rest of 78,75 g = 39,375 mol H2 is not used.
Post Reply