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Grade 11Physical Chemistry

The heat of reaction for N2+3H2---》2NH3 at 27°C is -91.94KJ. What will be its value at 50°C? The molar heat capacities at constant pressure and 27°C for N2, H2
and NH3 are 28.45, 28.32 and 37.07 joule respectively.

Profile image of Nikecr7
8 Years agoGrade 11
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1 Answer

Profile image of Shweta Ahire
7 Years ago
Delta H1 =91940joule 
T1= 300k ,  T2 =323 k
Delta C( heat capacity)=2(37.07) - 3(28.32) - 28.45= - 39.27joule
According to the kirchoffs law ,
Delta C =( delta H2 - delta H1 )/ ( T2 - T1 )
 So, -39.27 =( deltaH2 + 91940 joule )/(323 - 300)
By solving this , Delta H2 = 92.843 KJ