The equation below represents the combination of gaseous atoms of non-metal X and of
hydrogen to form gaseous X2H6
molecules.
2X(g) + 6H(g) → X2H6(g) ∆H = –2775kJmol
The bond energy of an X–H bond is 395kJmol
What is the bond energy of an X–X bond?
some help would be really appreciated : )
hydrogen to form gaseous X2H6
molecules.
2X(g) + 6H(g) → X2H6(g) ∆H = –2775kJmol
The bond energy of an X–H bond is 395kJmol
What is the bond energy of an X–X bond?
some help would be really appreciated : )
-
That reaction you've written is all bond-making.
You don't need to break any bonds, as the reactants are already single atoms.
So the enthalpy change is all due to the making of bonds.
You make 6 moles of X-H bonds, and one mole of X-X bonds., and it evolves 2775 kJ
but you know that the 6 X-H bonds are responsible for 6 x 395 kJ of that energy (= 2370kJ)
and the rest must be coming from the X-X bond.
You don't need to break any bonds, as the reactants are already single atoms.
So the enthalpy change is all due to the making of bonds.
You make 6 moles of X-H bonds, and one mole of X-X bonds., and it evolves 2775 kJ
but you know that the 6 X-H bonds are responsible for 6 x 395 kJ of that energy (= 2370kJ)
and the rest must be coming from the X-X bond.