When 1.8 g of an unknown salt, A2B3 is added to a calorimeter containing 82 ml of water at 26.8 °C the temperature change is -0.51 °C. In a subsequent experiment the molar mass of salt AB is determined to be 27.4 g/mole. Determine the molar enthalpy, A Hrzn(e) for the reaction. Assume the salt completely ionizes in water, that the density of the solution is 1.0 g/ml and that the specific heat of the solution is the same as that for water 4.18 J/(g°C)
Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
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