Delta H given

[505095793]

Why is it that when delta H is given in a thermodynamics question that this implies constant pressure?

[Jane Burgan 1C]

Delta H is the change in enthalpy, and the definition of enthalpy is that it is heat released or absorbed under constant pressure. So, when you're given delta H you know that there's constant pressure.

[Kyither Min 2K]

It is because the definition of delta H is the change in enthalpy of a reaction under constant pressure. Therefore, you know when delta H is given, the reaction took place under constant pressure.