Question

Use Hess's Law and equations B and C to find the enthalpy change for equation A.A.) -1287.5 kJB.) 4356.9 kJC.) 2822.2 kJD.) 1278.5 kJ

Answer 1

The enthalpy change for equation A is -1287.5kJ.

Step-by-step explanation:

1st) We have to write the equations B and C in order to obtain the final equation A:

`\begin{gathered} B)2C_2H_4+6O_2\rightarrow4CO_2+4H_2O \\ C)4CO_2+5H_2O\rightarrow C_4H_9OH+6O_2 \\ ---------------- \\ A)2C_2H_4+H_2O\rightarrow C_4O_9OH \end{gathered}`

2nd) In this case, the 4 moles of CO2, the 4 moles of H20 and the 6 moles of O2 cancel each other, without the need to multiply or divide the equations. So, we have to add the enthalpy of both equations:

`\begin{gathered} \Delta H_A=\Delta H_B+\Delta H_C \\ \Delta H_A=-2822.2kJ+1534.7kJ \\ \Delta H_A=-1287.5kJ \end{gathered}`

Finally, the enthalpy change for equation A is -1287.5kJ.