ThermochemistryMedium
Question
If x1, x2 and x3 are enthalpies of H - H, O = O and O - H bonds respectively, and x4 is the enthalpy of vaporisation of water, estimate the standard enthalpy of combustion of hydrogen.
Options
A.x1 + 
- 2x3 + x4
- 2x3 + x4B.x1 + - 2x3 - x4
- 2x3 - x4C.x1 + - x3 + x4
- x3 + x4D.2x3 - x1 - x4
- x4Solution
H2 (g) + 
O2 (g) → H2O (l) ; ᐃHcomb,H2
ᐃHcomb = ᐃHH − H +
ᐃHO = O - 2ᐃHO − H - ᐃHvap = x1 + 
-2x3 - x4
O2 (g) → H2O (l) ; ᐃHcomb,H2ᐃHcomb = ᐃHH − H +
ᐃHO = O - 2ᐃHO − H - ᐃHvap = x1 + -2x3 - x4Create a free account to view solution
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