Standard enthalpy changes?
(a) Which enthalpy change is represented by p?
CH4(g) → CH3(g) + H(g) ΔH ○ = p
1- mean bond enthalpy
or
2- bond enthalpy
(b) Which enthalpy change is represented by q?
CH4(g) → C(g) + 4H(g) ΔH ○ = 4q
1- mean bond enthalpy
or
2- bond enthalpy
-----------------------------
could you please explain the answer
CH4(g) → CH3(g) + H(g) ΔH ○ = p
1- mean bond enthalpy
or
2- bond enthalpy
(b) Which enthalpy change is represented by q?
CH4(g) → C(g) + 4H(g) ΔH ○ = 4q
1- mean bond enthalpy
or
2- bond enthalpy
-----------------------------
could you please explain the answer
Original post by reb0xx
(a) Which enthalpy change is represented by p?
CH4(g) → CH3(g) + H(g) ΔH ○ = p
1- mean bond enthalpy
or
2- bond enthalpy
(b) Which enthalpy change is represented by q?
CH4(g) → C(g) + 4H(g) ΔH ○ = 4q
1- mean bond enthalpy
or
2- bond enthalpy
-----------------------------
could you please explain the answer
CH4(g) → CH3(g) + H(g) ΔH ○ = p
1- mean bond enthalpy
or
2- bond enthalpy
(b) Which enthalpy change is represented by q?
CH4(g) → C(g) + 4H(g) ΔH ○ = 4q
1- mean bond enthalpy
or
2- bond enthalpy
-----------------------------
could you please explain the answer
Its better that you post it in the chemistry thread.
I could have helped you had it appeared an year earlier, but i haven't done chemistry from an year now so can't help.
a) Ans 2- bond enthalpy, as you are only taking one H off.
As soon as you take one H off the environment for the other protons changes.
So this bond enthalpy is specifically for taking off the first hydrogen in methane.
b) Ans is 1-mean bond enthalpy for methane.
You are taking all four off and then averaging the enthalpy change.
As the environment changes if you successively take off Hs, the bond enthalpy for each H differs.
(So the average, q, is not equal to p.)
As soon as you take one H off the environment for the other protons changes.
So this bond enthalpy is specifically for taking off the first hydrogen in methane.
b) Ans is 1-mean bond enthalpy for methane.
You are taking all four off and then averaging the enthalpy change.
As the environment changes if you successively take off Hs, the bond enthalpy for each H differs.
(So the average, q, is not equal to p.)
(edited 12 years ago)
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