Answer:
Calorimeter
Explanation:
As the name suggest "Calori-meter", calorie is the unit of energy or heat.
So it is the apparatus which is used to measure energy transfer during any physical or chemical change like phase change.
Calorimeter can be open (constant pressure)
Calorimeter can be closed (constant colume)
If we measure heat change in open calorimeter then it gives enthalpy change of any chemical or physical change.
