Please help me with this hess law ive been working on for hours!!?

M

MeMe123

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2C (graphite) + 3H2 (g) -----> C2H6 (g)

From the following data...
C (graphite) +O2 ---> CO2
H2 + 1/2O2 ---> H2O
2C2H6 + 7O2 ---> 4CO2 + 6H20
Calculate the enthalpy change for the reaction below:
2C(graphite) +3H2(g)-->C2H6(g)
2C (graphite) + 3H2 (g) -----> C2H6 (g)

From the following data...
C (graphite) +O2 ---> CO2 -393.5
H2 + 1/O2 ---> H2O -285.8
2C2H6 + 7O2 ---> 4CO2 + 6H20 -3119.6
 
From the following data...
C (graphite) +O2 ---> CO2 -393.5
H2 + 1/2O2 ---> H2O -285.8
2C2H6 + 7O2 ---> 4CO2 + 6H20 -3119.6


2C (graphite) +2O2 ---> 2CO2 -393.5X2
3H2 + 3/2O2 ---> 3H2O -285.8X3
2CO2 + 3H20 ---> C2H6 + 7/2O2 -3119.6
reverse and divide by 2=+3119.6/2

-->2C(graphite) +3H2(g)-->C2H6(g)
enthapy change =-393.5X2 -285.8X3+3119.6/2
=-84.6
 
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