Gh0strid3r
Badges: 4
Rep:
?
#1
Report Thread starter 2 years ago
#1
How to calculate heat transfer using bond energies
(IGCSE)/ olevels
0
reply
username2752874
Badges: 22
Rep:
?
#2
Report 2 years ago
#2
(Original post by Gh0strid3r)
How to calculate heat transfer using bond energies
(IGCSE)/ olevels
Use the formula:

Enthalpy Change (or heat transfer) = Energy of the bonds broken - Energy of the bonds formed

Remember, bond breaking is positive while bond forming is negative
1
reply
Sonia2598
Badges: 13
Rep:
?
#3
Report 2 years ago
#3
Is there a question for it?
1
reply
Gh0strid3r
Badges: 4
Rep:
?
#4
Report Thread starter 2 years ago
#4
Name:  B26B65B4-D0A6-4AA5-8DD8-40312B85573A.jpg.jpeg
Views: 56
Size:  18.9 KB
0
reply
Gh0strid3r
Badges: 4
Rep:
?
#5
Report Thread starter 2 years ago
#5
(Original post by Sonia2598)
Is there a question for it?
Yes please the question is posted can u help
0
reply
Sonia2598
Badges: 13
Rep:
?
#6
Report 2 years ago
#6
So you do sum of energy required to break bonds which is the reactants minus sum of energy required to form bonds which is the products

So 678-862= -184KJ
0
reply
gingembread
Badges: 3
Rep:
?
#7
Report 2 years ago
#7
Overall energy change = (energy required to break bonds) - (energy released by forming bonds).

So, if you calculate the energy needed to break the H-H and the Cl-Cl bond using the data in the table, and subtract the energy released by forming two H-Cl bonds, you'll get the overall energy change.

Exothermic reactions are when energy is released to the surroundings, so the energy released by breaking bonds is greater than the energy used to break them. You can prove this by getting an overall energy change that's negative from this calculation. (:
1
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Do you have the space and resources you need to succeed in home learning?

Yes I have everything I need (74)
63.79%
I don't have everything I need (42)
36.21%

Watched Threads

View All