Standard change of enthelpy, hess's law question

Click For Summary
SUMMARY

The discussion centers on applying Hess's Law to calculate the standard change of enthalpy for a reaction involving hydrogen (H2), oxygen (O2), and hydrazine (N2H4) to produce ammonia (NH3). The user attempted to manipulate the reaction equations by multiplying the H2 + 1/2O2 equation by 3 to align with the products but faced challenges in balancing the nitrogen component (4N2). The user seeks guidance on whether to divide all components by four to achieve the correct stoichiometry.

PREREQUISITES
  • Understanding of Hess's Law and its application in thermodynamics.
  • Familiarity with balancing chemical equations.
  • Knowledge of standard enthalpy changes and their significance.
  • Basic skills in stoichiometry and mole ratios.
NEXT STEPS
  • Study Hess's Law in detail, focusing on its mathematical applications.
  • Practice balancing complex chemical equations involving multiple reactants and products.
  • Learn about standard enthalpy of formation and how to use it in calculations.
  • Explore examples of enthalpy calculations in thermodynamic textbooks or online resources.
USEFUL FOR

Chemistry students, educators, and anyone involved in thermodynamics or chemical engineering who seeks to deepen their understanding of enthalpy changes and reaction stoichiometry.

gurpalc
Messages
16
Reaction score
0

Homework Statement



http://imgur.com/lb0HL

Homework Equations



in pic

The Attempt at a Solution



So I multiplied the H2 + 1/2O2 equation by 3 and added it to the (N2H4, 2NH3) equation.

I got H2O to match up and O2 to match up, but I don't know how to manipulate the other

equations to get 4N2 to match up. Do I divide all by four? I don't know.
Please help.
Thanks
 
Physics news on Phys.org
please copy and paste the question -- do not link it; I have no way of knowing whether it is a scam link.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
5K
Replies
1
Views
27K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 16 ·
Replies
16
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
6
Views
3K
Replies
8
Views
8K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 2 ·
Replies
2
Views
5K