Two substances, lead and granite, initially at different temperatures, come into contact and reach thermal equilibrium. The mass of lead is 20.4 gg and its initial temperature is 55.7 ∘C∘C. The mass of granite is 18.7 gg and its initial temperature is 22.7 ∘C∘C. What is the final temperature of both substances at thermal equilibrium? (The specific heat capacity of lead is 0.128 J/(g⋅∘C)J/(g⋅∘C); the specific heat capacity of granite is 0.79 J/(g⋅∘C)J/(g⋅∘C).)
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) Two substances, lead and granite, initially at different temperatures, come into contact and reach thermal equilibrium. The mass of lead is 20.4 gg and its initial temperature is 55.7 ∘C∘C. The mass of granite is 18.7 gg and its initial temperature is 22.7 ∘C∘C. What is the final temperature of both substances at thermal equilibrium? (The specific heat capacity of lead is 0.128 J/(g⋅∘C)J/(g⋅∘C); the specific heat capacity of granite is 0.79 J/(g⋅∘C)J/(g⋅∘C).)
b) A 4.03 gg sample of gold, initially at 70.4 ∘C∘C, is submerged into 60.8 gg of water at 17.8 ∘C∘C in an insulated container. What is the final temperature of both substances at thermal equilibrium? (The specific heat capacity of gold is 0.128 J/(g⋅∘C)J/(g⋅∘C);the specific heat capacity of water is 4.18 J/(g⋅∘C)J/(g⋅∘C).)
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