molar enthalpy of formation
 

I wish to determine the molar heat of formation for sodium sulphide (Na2S).
I designed an investigation wehre 11.4 g of hydrogen sulphide gas (H2S) was completely reacted with the solid sodium hydroxide in a bomb calorimeter producing solid sodium sulphide and liquid water. The 250 mL of water in the calorimeter changed in temperature from 23.2 degrees celcisu to 43.8 degrees celcius. Assuming only the calorimeter water gained the heat energy, I wanted to calculate the moalr heat of formation for sodium sulphide.

Ok Here, are my calculations:

Delta Hr = q
nHr = mc delta t

11.4g(1mol/34.08g)(H) = 0.25 kg(4.19Kj/Kg dot degrees C)(20.6 degrees C)
0.3286384977mol(H) = 21.5785 kJ
H=65.7 kJ/mol

Now my question is: Did I find what I was looking for? I'm getting the inkling I found the molar enthalpy for Hydrogen sulphide gas instead of the molar heat of formation for sodium sulphide.

If did my calculations wrong, and found the Hydrogen sulphide instead, would you be able to show me how to find the sodium sulphide?

That's the enthalpy of formation of Na2S.

Oh, thank you!