100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Previously searched by you
Previously searched by you
logo
Summary Hess's Law $2.99   Add to cart
Quickly navigate to
Preview
  2.  
  3. Junior / 11th Grade
  4.  
  5. Chemistry

Summary

Summary Hess's Law
 8 views  0 purchase
  • Course
  • Chemistry
  • Institution
  • Junior / 11th Grade

The PDF explains Hess's Law, which states that the total enthalpy change of a chemical reaction is independent of the reaction pathway as long as the initial and final conditions are the same. It introduces Hess cycles, illustrating how to use them to calculate enthalpy changes that cannot be deter...

[Show more]

Preview 2 out of 9  pages

Document information

  • October 3, 2024
  • 9
  • 2024/2025
  • Summary

Subjects

Written for

  • Junior / 11th grade
  • Chemistry
  • 3

Seller

avatar-seller
haydenash

Content preview

Head to www.savemyexams.com for more awesome resources




CIE AS Chemistry Your notes

5.2 Hess’s Law
Contents
Hess’s Law




Page 1 of 9

© 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers

, Head to www.savemyexams.com for more awesome resources




Hess’s Law
Your notes
Hess Cycles
Hess’s Law states that:
"The total enthalpy change in a chemical reaction is independent of the route by which the chemical
reaction takes place as long as the initial and final conditions are the same."
This means that whether the reaction takes place in one or two steps, the total enthalpy change of the
reaction will still be the same
Illustration of Hess's Law




According to Hess’ Law, the enthalpy change of the direct route, going from reactants (A+B) to
product (C), is equal to the enthalpy change of the indirect routes
Hess’ Law is used to calculate enthalpy changes which can’t be found experimentally using
calorimetry, e.g.:
3C (s) + 4H2 (g) → C3H8(g)
ΔHf (propane) can’t be found experimentally as hydrogen and carbon don’t react under standard
conditions

Calculating ΔHr from ΔHf using Hess’s Law energy cycles
The products can be directly formed from the elements = ΔH2
OR
Page 2 of 9

© 2015-2024 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller haydenash. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for $2.99. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

67474 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 14 years now

Start selling
$2.99
  • (0)
  Add to cart