Suppose you have 125 mL of coffee in a well-insulated cup, but the coffee is at 92oC, which is too hot to drink. What volume of cold milk at 12oC would you have to add to reduce the temperature of the coffee to 72oC? Q = m x c x deltaT HINT: The heat lost by the coffee must be gained by the milk so -Qcoffee = Qmilk *** Assume coffee and milk have the same specific heat and density as water: cH2O = 4.184 J/(g oC); dH2O = 1 g/ml
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.
Suppose you have 125 mL of coffee in a well-insulated cup, but the coffee is at 92oC, which is too hot to drink. What volume of cold milk at 12oC would you have to add to reduce the temperature of the coffee to 72oC? Q = m x c x deltaT HINT: The heat lost by the coffee must be gained by the milk so -Qcoffee = Qmilk
*** Assume coffee and milk have the same specific heat and density as water:
cH2O = 4.184 J/(g oC); dH2O = 1 g/ml
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