Chemistry: Algebra Combining Equations [Enthelpy]

  • Thread starter Thread starter intellekt
  • Start date Start date
  • Tags Tags
    Algebra Chemistry
Click For Summary
SUMMARY

The discussion centers on the application of Hess's Law to algebraically combine equations related to the change in enthalpy for a lab analysis involving magnesium combustion. The user seeks clarification on whether to change the signs of the enthalpy values before summing them to derive the overall enthalpy change for the reaction. It is established that Hess's Law allows for the combination of enthalpy changes from multiple reactions to determine the enthalpy change of a target reaction.

PREREQUISITES
  • Understanding of Hess's Law and its application in thermodynamics
  • Familiarity with enthalpy changes in chemical reactions
  • Basic algebra skills for combining equations
  • Knowledge of combustion reactions, specifically involving magnesium
NEXT STEPS
  • Study the principles of Hess's Law in detail
  • Practice combining multiple chemical equations to calculate enthalpy changes
  • Explore examples of enthalpy changes for various combustion reactions
  • Learn about the significance of sign changes in thermodynamic equations
USEFUL FOR

Chemistry students, lab analysts, and educators seeking to deepen their understanding of thermodynamic principles and the application of Hess's Law in calculating enthalpy changes.

intellekt
Messages
3
Reaction score
0
Hi, I am stuck on this one question for a lab analysis I am doing. I missed the class where the teacher explained this and a lot more stuff. I also recall a question like this on a test I wrote on friday:smile:

Anyway here it is:

Algebraically combine equations (2), (3), and (4) and their corresponding [Change in Enthalpy] values, to get (1) and [Change in Enthalpy] of combustion of magnesium.

I just need to know how to do it, I can plug in the values after right?

Let me know! thanks in advance!
 
Physics news on Phys.org
Have you learned about Hess's Law?
"[URL
Your question requires a direct application of Hess's Law.
 
Last edited by a moderator:
Ya I have learned Hess' law but I'm still unsure...

So do I change the signs then add them together to get the enthalpy of equation 1?
 
Last edited:

Similar threads

Chemistry Understanding the calculation of enthalpy of the formation of benzene
  • · Replies 3 ·
Replies
3
Views
4K
How do I calculate the enthelpy of formation using combusion data
  • · Replies 9 ·
Replies
9
Views
7K
Chemistry Where Did the 400g in Enthalpy Change of Neutralization Come From?
  • · Replies 3 ·
Replies
3
Views
3K
Chemistry A calculation of enthalpy, entropy, and Gibbs energy of vaporization
  • · Replies 1 ·
Replies
1
Views
3K
Chemistry Calculation of thermodynamic variables for irreversible adiabatic process of ideal gas
  • · Replies 9 ·
Replies
9
Views
3K
Chemistry Create a Gibbs Free Energy challenge question
  • · Replies 1 ·
Replies
1
Views
3K
Calculate the change in entropy for the system and the surroundings
  • · Replies 13 ·
Replies
13
Views
4K
How do I know which enthelpy change to calculate?
  • · Replies 2 ·
Replies
2
Views
2K
Chemistry Finding the molecular formula of an unknown hydrocarbon
  • · Replies 4 ·
Replies
4
Views
3K
Chemistry homework help with enthelpy
  • · Replies 3 ·
Replies
3
Views
3K