In this experiment you will place a sample of your salt in water in a constant pressure calorimeter with a heat capacity of 29.4 J/℃. You will determine the enthalpy change for the dissociation of your salt, Delta Hdiss. A sample of 4.368 grams of the salt SrCl2 was placed in 35.5 g water, the initial temperature was 20.00℃ and the final temperature was 27.086365℃. Now that we have the enthalpy of reaction, q (reaction) = – 1390.399457 J, and the number of moles 0.035491131 mol SrCl2 , we can get the enthalpy of reaction. Give Delta H (rxn) in correct sig figs. Delta H (rxn) = q / n = – 1390.399457 J / 0.035491131 mol SrCl2 Delta H (rxn) = – 39175.96895 J / mol SrCl2 Delta H (rxn) = – 39.17596895 kJ / mol SrCl2 Select one: a. none of these b. – 39.17596895 kJ / mol c. – 39 kJ / mol d. – 4 x 10^1 kJ / mol e. – 39.18 kJ / mol f. – 39.1 kJ / mol g. – 39.17 kJ / mol h. – 39.2 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.
This and the following questions pertain to the following problem: In this experiment you will place a sample of your salt in water in a constant pressure calorimeter with a heat capacity of 29.4 J/℃. You will determine the enthalpy change for the dissociation of your salt, Delta Hdiss. A sample of 4.368 grams of the salt SrCl2 was placed in 35.5 g water, the initial temperature was 20.00℃ and the final temperature was 27.086365℃. Now that we have the enthalpy of reaction, q (reaction) = – 1390.399457 J, and the number of moles 0.035491131 mol SrCl2 , we can get the enthalpy of reaction. Give Delta H (rxn) in correct sig figs.
Delta H (rxn) = q / n = – 1390.399457 J / 0.035491131 mol SrCl2
Delta H (rxn) = – 39175.96895 J / mol SrCl2
Delta H (rxn) = – 39.17596895 kJ / mol SrCl2
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