Question

The phrase “the heat absorbed or released by a system undergoing a physical or chemical change at constant pressure” is

a. the change in enthalpy of the system.
b. the change in internal energy of the system.
c. the definition of a state function.
d. the temperature change of the system.
e. a statement of Hess’s law.

Answer 1

Can you explain why?

Answer 2

Here is some reading for you. Pay particular attention to paragraphs 4 and 5.
http://en.wikipedia.org/wiki/Enthalpy

Answer 3

i want the answer dumb butt not a source