Enthalpy Units

[bonnie_schmitz_1F]

What are the units for enthalpy? Sometimes its written in kJ but other times its kJ mol-1. Is there a difference?

[emily gao 1C]

enthalpy is in some kind of joules (J, kJ, etc). kJ/mol is just per mole what is the enthalpy
aka its not too significant

[Helen Zhao 1F]

Enthalpy is the amount of heat released or absorbed at constant pressure. Whether or not it's kJ or kJ * mol^-1, it doesn't really matter. Just remember to use the units that best fits the question asked.

[Simmi Diwanji 2B]

I think enthalpy could be either kJ or kJ/mol but the standard enthalpy of formation always must be kJ/mol.

[maldonadojs]

I do not believe that there is a difference, but it follows the information given by the problem.

[Anjali_Kumar1F]

What is the standard enthalpy of formation?

[Simran Rai 4E]

The standard enthalpy of formation is the enthalpy change when 1 mole of a substance is formed from its element(s). Note that all the substances should be in standard state.

[ran2000]

It depends on the situation. When considering a free reaction, we consider kJ since that is the exact amount of energy being released or absorbed. But, when we consider the situation where in we are considering a standard reaction (ex: Haber's process for 1 mol of ammonia), then we write kJ mol-1 to indicate the energy per unit.