Hey please help me to explain this topic. I only need answer in typed format. DO
ID: 1030795 • Letter: H
Question
Hey please help me to explain this topic. I only need answer in typed format. DOn't post any picture in solution. And be specific and easy to grasp.
Hess' Principle
Use the following information to calculate the heat of formation of propane, C3H8.
3 C (graph) + 4 H2 (g) ® C3H8 (g)
1. C (graph) + O2 (g) ® CO2 (g) DH = - 393.5 kJ
2. H2 (g) + ½ O2 (g) ® H2O (l) DH = - 285.8 kJ
3. C3H4 (g) + 4 O2 (g) ® 3 CO2 (g) + 2 H2O (l) DH = - 1937 kJ
4. C3H6 (g) + 9/2 O2 (g) ® 3 CO2 (g) + 3 H2O (g) DH = - 2007 kJ
5. C3H8 (g) + 5 O2 (g) ® 3 CO2 (g) + 4 H2O (l) DH = - 2219.1 kJ
Explanation / Answer
C (graph) + O2 (g) ® CO2 (g) DH = - 393.5 kJ
3C (graph) + 3O2 (g) ® 3CO2 (g) DH = - 393.5*3 kJ--------------i
H2 (g) + ½ O2 (g) ® H2O (l) DH = - 285.8 kJ
4 H2 (g) + 2O2 (g) ® 4H2O (l) DH = - 285.8*4 kJ-------------ii
adding i+ii
3C (graph) + 3O2 (g) + 4 H2 (g) + 2O2 (g) ® 3CO2 (g) + 4H2O (l) DH=-393.5*3+(-285.8*4) kJ = -2323.7 kJ ----iii
C3H8 (g) + 5 O2 (g) ® 3 CO2 (g) + 4 H2O (l) DH = - 2219.1 kJ
3 CO2 (g) + 4 H2O (l) ® C3H8 (g) + 5 O2 (g) DH = 2219.1 kJ-----------iv
iv+iii
3 CO2 (g) + 4 H2O (l) + 3C (graph) + 3O2 (g) + 4 H2 (g) + 2O2 (g) ® C3H8 (g) + 5 O2 (g) +3CO2 (g) + 4H2O (l)
DH=2219.1-2323.7= 104.6 kJ
so finally we get the result i.e.
3 C (graph) + 4 H2 (g) ® C3H8 (g) DH= 104.6 kJ