The heat of combustion of acetylene is 312 kcal . If heat of formation of CO2 and H2O are 94.38 and 68.38 kcal respectively , calculate C triple bond C energy . Given that heat of atomization of C and H are 150 and 51.5 kcal respectively and C-H bond energy is 93.64 kcal.
now i think i am making a calculation error here... :-\
i have added twice the heat of C-H bond , bond energy of C triple bond C ( let it be x ) , twice the heat of formation of CO2 and heat of formation of H2O and also the two heat of atomizations and equated it to 312 kcal.........but not getting the right answer......where am i wrong?? ??? ???
30edit:
C2H2 + 2.5O2→ 2CO2 + H2O
ΔHc=-312kcal (Assuming it..since you have not given negative signs for any of them)
ΔHc = ΣΔH°f(P) - ΣΔH°f(R)
= -(2*94.38 + 68.38) - ( x + 2*150 + 51.5 - 2*93.64) [ 2C(g) + H2(g) → C2H2(g) ]
= -257.14 - x - 351.5 + 187.28
ΔHC≡C = -109.36 kcal
1Very easy question answer is coming as 160.86 kcal/mol
[in the above answer i m assuming by heat of formation of CO2 and H2O are 94.38 and 68.38 kcal u meant to say that heat of formation of CO2 and H2O are -94.38 and -68.38 kcal]
plz correct the problem accordingly[1]
1jab se chem mein thermo aya[1]
btw cn u post solution to the first problem here as no one except u seems to get the answer mentioned as 1 L in book
http://www.targetiit.com/iit-jee-forum/posts/gaseous-state-18718.html
39I believe he's referring to -:
"Lavoisier and Laplace’s law : The energy change accompanying any transformation is equal and opposite to energy change accompanying the reverse process"
1ya wahi wala....m weak at remembering these idiotic laws(especially the name of founder's :P....but still i m patting my back for remembering half of it[3])
6can u just show what u did??coz i think i m doin a real stupid calculation mistake..