The heat capacity of air is much smaller than that of liquid water, and relatively modest amounts of heat are therefore needed to change the temperature of air. This is one of the reasons why desert regions, though very hot during the day, are bitterly cold at night. The molar heat capacity of air at 298 K and 1.00 atm is approximately 21 J K−1 mol−1. Estimate how much energy is required to raise the temperature of the air in a room of dimensions 5.5 m × 6.5 m × 3.0 m by 10 °C. If losses are neglected, how long will it take a heater rated at 1.5 kW to achieve that increase, given that 1 W = 1 J s−1?
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.
The heat capacity of air is much smaller than that of liquid water, and relatively modest amounts of heat are therefore needed to change the temperature of air. This is one of the reasons why desert regions, though very hot during the day, are bitterly cold at night. The molar heat capacity of air at 298 K and 1.00 atm is approximately 21 J K−1 mol−1. Estimate how much energy is required to raise the temperature of the air in a room of dimensions 5.5 m × 6.5 m × 3.0 m by 10 °C. If losses are neglected, how long will it take a heater rated at 1.5 kW to achieve that increase, given that 1 W = 1 J s−1?
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