“c” the specific heat capacity of a substance is given by temperature difference is given by ΔT and the heat energy is given by Q then what is the mass of the substance?

The heat evolved at constant volume, and heat change at constant pressure is measured using a calorimeter. The process is called Calorimetry.

Bomb Calorimeter is used to measure the ∆U, while a coffee calorimeter is used to measure ∆H.

Calorimetry also helps in determining if a reaction is endothermic or exothermic.