A bar person is asked to serve 200 mL of orange juice (density 1.25 g/ml, c = 1.77 kJ/kg K) at 8°C. The orange juice is initially at 12 °C and has to be cooled down by putting a number of steel cubes into the juice each of 45 g (c = 624 J/kg K) at 1°C. How many steel cubes should be put into the orange juice to reach the desired temperature?
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 bar person is asked to serve 200 mL of orange juice (density 1.25 g/ml, c = 1.77 kJ/kg K) at 8°C. The orange juice is initially at 12 °C and has to be cooled down by putting a number of steel cubes into the juice each of 45 g (c = 624 J/kg K) at 1°C. How many steel cubes should be put into the orange juice to reach the desired temperature?
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