Is delta H a state function?(Hess Law?)

[sachin123]

is delta H a state function??(Hess Law?)

Is delta H a state function?

We know that delta H=delta U+W (at const P)
so,
we also know that W is path dependent function.So delta H being a sum of delta U and a path dependent function must not be a state function.(point 1)

But there is this Hess Law which allows you to add 2 chemical reactions along with their enthalpy changes.
Lets say water is formed from H2 and O2.lets say water is again formed from H2 and O2 but in a different path.according to Hess law,delta H is same in both cases.
Now doesn't that make delta H a state function?(point 2)

Don't point 1 and point 2 contradict?
Thank You.

 

[Mapes]

We know that delta H=delta U+W (at const P)
so,
we also know that W is path dependent function.

What if W is no longer path dependent when you fix P?

 

[sachin123]

oh.so even W is a state function in this case then.
so that makes H a state function in general.
Thank you Mapes

 

[sachin123]

Also may I extend this and ask,
why are different sign conventions used for 'Work' in physics and chemistry?
in physics we take W +ve when work is done by the system and correspondingly we take it -ve in chemistry.Is there any significance?

 

[weng cheong]

however i read a text saying that, 'delta H has a defined value for a particular change, regardless of whether or not it's at constant pressure'.

in this case, W is not a state function. then how is it possible?