A 50.0 mL sample of 0.5 M AgNO3(aq) is mixed with a 50.0 mL sample of 0.5 M NaI(aq) in a calorimeter. The temperature of both solutions was 22.9oC before mixing and 31.8oC after mixing. The heat capacity of the calorimeter was 18.7 J/oC. From these data, calculate the ∆Hrxn in units of kJ/mol for the following reaction: AgNO3(aq) + NaI(aq) ==> AgI(s) + NaNO3(aq) Assume the specific heat and density of the solution after mixing are the same as those of pure water; specific heat capacity = 4.184 J/goC; density = 1.00 g/mL. -160 kJ/mol 150 kJ/mol -3.9 x 103 kJ/mol 160 kJ/mol -150 kJ/mol -3.7 x 103 kJ/mol
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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A 50.0 mL sample of 0.5 M AgNO3(aq) is mixed with a 50.0 mL sample of 0.5 M NaI(aq) in a calorimeter. The temperature of both solutions was 22.9oC before mixing and 31.8oC after mixing. The heat capacity of the calorimeter was 18.7 J/oC. From these data, calculate the ∆Hrxn in units of kJ/mol for the following reaction:
AgNO3(aq) + NaI(aq) ==> AgI(s) + NaNO3(aq)
Assume the specific heat and density of the solution after mixing are the same as those of pure water; specific heat capacity = 4.184 J/goC; density = 1.00 g/mL.
-160 kJ/mol
150 kJ/mol
-3.9 x 103 kJ/mol
160 kJ/mol
-150 kJ/mol
-3.7 x 103 kJ/mol
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