Fill This Form To Receive Instant Help
Homework answers / question archive / Calculate the standard enthalpy change for the reaction 2A+B?2C+2D Use the following data: Substance ?H?f (kJ/mol) A -249 B -389 C 217 D -483 ?H?rxn = 355 kJ For the reaction given in Part A, how much heat is absorbed when 3
Calculate the standard enthalpy change for the reaction
2A+B?2C+2D
Use the following data:
Substance | ?H?f (kJ/mol) |
A | -249 |
B | -389 |
C | 217 |
D | -483 |
?H?rxn = |
355 kJ For the reaction given in Part A, how much heat is absorbed when 3.10mol of A reacts? Express your answer to three significant figures and include the appropriate units. |
2A + B <-------> 2C + 2D ;
Delta H0rkn = 2*[delta H0f D] + 2*[delta H0f C] - [delta H0f B] - 2*[delta H0f A] = 355 kJ
Now, Assuming that while reacting with 3.1 moles of reactant A, all other reactants are in excess
Thus, for reacting with 3.1 moles of A, moles of B required = (1/2)*moles of A = 1.55
moles of C formed = moles of D formed = moles of a A reacting = 3.1
Thus, heat absorbed in the reaction
= 3.1*[delta H0f D] + 3.1*[delta H0f C] - 1.55*[delta H0f B] - 3.1*[delta H0f A]
(3.1*-483) + (3.1*217) - (1.55*-389) - (3.1*-249)= 550.25 kJ