A solution prepared by mixing 8.00 g of NaOH in 50.0 g of H2O is mixed together with a solution prepared by mixing 8.00 g of HCl (36.46 g/mol) in 250.0 g of H2O in a coffee-cup calorimeter. The following reaction takes place: HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(aq) Both solutions were initial at 25 °C and after mixing the maximum temperature recorded in the calorimeter was 33.5°C. Assuming that the specific heat of the final mixture is 4.18 J/g°C, calculate ΔH for the reaction in kJ/mol (where mol represents the limiting reagent).
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.
A solution prepared by mixing 8.00 g of NaOH in 50.0 g of H2O is mixed together with a solution prepared by mixing 8.00 g of HCl (36.46 g/mol) in 250.0 g of H2O in a coffee-cup calorimeter. The following reaction takes place: HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(aq) Both solutions were initial at 25 °C and after mixing the maximum temperature recorded in the calorimeter was 33.5°C. Assuming that the specific heat of the final mixture is 4.18 J/g°C, calculate ΔH for the reaction in kJ/mol (where mol
represents the limiting reagent).
The formula of heat is given by:
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