Question

Calculate the value of ?H

Answer 1

your question misses some data so i gave a similar example so that u could do for any sum hope u wil get some info and rate if it helps u

Given the following data:
C2H2 + 2.5O2 ? 2CO2 + H2O DH = ?1300 kJ
C + O2 ? CO2 DH = ?394 kJ
H2 + 0.5O2 ? H2O DH = ?286 kJ
Calculate DH for the reaction
2C + H2 ? C2H2

SOLUTION

Reason:

the goal is to get to the reaction
2C + H2 ? C2H2
The only way you can do that is to use the other equations and multiply them.

C2H2 + 2.5O2 ? 2CO2 + H2O
flip the equation. That changes the energy multiplying it by a -1

C + O2 ? CO2
Double the equation and the delta H

H2 + 0.5O2 ? H2O
don't change

That gives you
2CO2 + H2O + 2C + 2O2 + H2 + 0.5O2 ? C2H2 + 2.5O2 + 2CO2 + H2O

Cancel out the components on both sides and end with
2C + H2 ? C2H2

The delta H would be
-1(-1300) + 2(-394) + -286 = 226 kJ