Enthelpy of the decomposition reaction of N2H4 gas

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SUMMARY

The discussion focuses on calculating the enthalpy change for the decomposition reaction of hydrazine (N2H4) gas into nitrogen (N2) and hydrogen (H2). The correct enthalpy change is determined to be -86.0 kJ, which is derived from the standard enthalpy values of the reactants and products. The calculation involves using the enthalpy of formation values: for N2H4, it is 163 kJ/mol; for H2, it is 436 kJ/mol; and for N2, it is 0 kJ/mol. The formula applied is ΔH = Σ(ΔHf products) - Σ(ΔHf reactants).

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lizgore94
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I am trying to determine the change of heat for:

N2H4(g) -> N2(g) + 2H2(g)

Here is what I did and what I got the correct answer is -86.0 which I am clearly not getting

[(163)+ (2*436)] - [(4*391) + (163)] = -692

thanks for any help!
 
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Where have all these numbers come from?
 

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