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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Rysix on March 07, 2015, 09:26:19 AM

Title: Exercice Of Thermochemistry Help Plz
Post by: Rysix on March 07, 2015, 09:26:19 AM

Hi,

The Qst Is : -calculate Enthalpy Of the Liaison between C N In HCN Molecule

Th Reaction Is : CH4(g) + NH3(g) ---> HCN(g) + 3H2

I Calculated before : The Enthalpy of formation HCN(g) = -113.5 Kj/mol

And It was Given : ΔH° H-H = -435.5 ; ΔH°N=N = -944.7 ; ΔH°C-H = -413.8 ; ΔH°sublimation Of C(s) = 718

For Me I Started With this  : 1/2 H2(g) + C(g) + 1/2 N2(g) ----> HCN(g)

But I don't really know how i can find out the relation to calculate Enthalpy of liaison C N ? Should I Make a Cycle ?! Help Please And Thanks

Title: Re: Exercice Of Thermochemistry Help Plz
Post by: billnotgatez on March 07, 2015, 10:51:52 AM

Click on the link near the top center of the forum page.
Forum Rules: Read This Before Posting.
You will notice that you only post a given question once on the forum
I removed your other 2 copies