Ans: Enthalpy is the alteration of the amount of heat in a system when the temperature is constant. Enthalpy is not the same as heat. Heat is an energy that transfers from one system to another or surrounding due to temperature differences. Students can consider enthalpy and heat as a single term under one condition. When there is no work done to the system, then we take both of them as the same. Scientists measure the enthalpy with the (international system of units) SI unit called Joule. Also, they use the unit ‘calorie’ for measuring enthalpy in different regions of Europe (British thermal Unit).