A 50.0 mL solution of 0.600 M compound A is mixed with an excess of compound B solution at 13.5° C in a styrofoam calorimeter (assume the heat capacity of the calorimeter is zero). The chemicals react to form compound C and water, and the temperature rises to 25.4 °C. If the mass of the total reaction solution is 195 g, calculate the molar enthalpy, AH, of the reaction (in J/mol). The specific heat capacity of the reaction solution is 4.184 J g 1•0
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.
The reaction will be written as
A+ B ---> C + H2O
mass of solution= 195 g
Heat capacity of solution= 4.184 j/g°C
Initial temperature= 13.5°C
Final temperature= 25.4°C
Temperature change "∆T" = T(final) - T(initial)
∆T = 25.4°C - 13.5°C = 11.9°C
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