# I need help in understanding State functions

1. Jun 19, 2013

### crashdirty86

1. The problem statement, all variables and given/known data

What is a state function? How is it different from a scalar quantity? Use the expression ΔH=q as an example.
2. Relevant equations

3. The attempt at a solution

So the way I am interpreting this question is that a state function is a reference to say the temperature, pressure, and amount of a substance, not how the substance is aquired, its present state. A scalar quantity would be an amount of say temperature, making it pathway dependent. Using teh above equation, I believe that the H-final and H-initial are state functions, and their sum is a scalar quantity that is not a state function.

I am really confused on this topic, any help would be much appreciated.

2. Jun 19, 2013

### Simon Bridge

It's just testing that you know the definition of a state function.
http://en.wikipedia.org/wiki/Functions_of_state

You seem to have the main point - to be a state function or variable, it's value must only depend on the state, while any old variable could depend on anything.

With reference to the relation provided - what are the variables supposed to represent?
Does the outcome (q) depend on how one gets from H_i to H_f ?