Posted by Ally on Tuesday, July 12, 2011 at 10:58pm.
RXN #1: H2 (g) + O2 (g) --> H2O2 (l) ; delta-H =?
Calculate the enthalpy change (delta-H1) for the reaction above (RXN #1) using the information below and Hess' Law.
RXN A: H2O2 (l) --> H2O (l) + 1/2 O2 (g); delta-H=-98.0 kJ/mol
RXN B: 2 H2 (g) + O2 --> 2 H2O (l); delta-H= -571.8 kJ/mol
- Chem - DrBob222, Tuesday, July 12, 2011 at 11:02pm
Reverse eqn A and add to 1/2 eqn B. Reversing an eqn changes sign of H. Taking 1/2 eqn changes H by 1/2.
- Chem - Ally, Tuesday, July 12, 2011 at 11:17pm
I don't see how that works
- Chem - DrBob222, Tuesday, July 12, 2011 at 11:45pm
1/2 eqn b.
2H2 + O2 ==> 2H2O becomes
H2 + 1/2 O2 ==> H2O
reverse eqn A.
H2O2 ==> H2O + 1/2 O2 becomes
H2O + 1/2 O2 ==> H2O2
.....H2 + 1/2 O2 ==>H20
+....H2O + 1/2O2 ==> H2O2
H2 + 1/2 O2 + H2O + 1/2 O2 >H2O + H2O2
1/2 O2 + 1/2 O2 = O2
H2O on left cancels with H2O on the right and you are left with
H2 + O2 ==> H2O2.
Now MY question. IF you actually tried this, and I suspect you didn't, what did you not understand? You've got to get your hands a little dirty if you want to work through these things.
- Chem - Ally, Wednesday, July 13, 2011 at 12:07am
Thanks You're the best!
Answer This Question
More Related Questions
- chemistry - At 25 C the following heats of reaction are known: 2CIf (g)+ O2(g...
- Chemistry - Calculate the DELTA H(rxn), DELTA S(rxn), DELTA S(universe), DELTA G...
- chemistry - Calculate the enthalpy of change, Delta H of rxn, for each of the ...
- Chemistry - For the reaction described by the chemical equation: 3C2H2(g) -> ...
- Chemistry - Enthalpy changes: H2O2(l) ----> H2O(l) + 1/2P2(g) delta H= -94....
- Chemistry - A rxn has delta H ^0 rxn=-112kj and delta S^0 rxn =354 J/K. at what ...
- Science - Hydrogen peroxide can be prepared in several ways. One method is the ...
- chemistry - The standard internal energy change for a reaction can be symbolized...
- Chemistry - The standard internal energy change for a reaction can be symbolized...
- Chemistry - Calculate the standard entropy, ΔS°rxn, of the following ...