1. An 800g aluminium block cools from 85°C to 30 °C. Calculate the heat capacity, C, of the aluminium block. 2. Construct an energy cycle diagram for potassium fluoride. 3. Determine the lattice energy of potassium fluoride. Enthalpy of atomization of potassium = +89.2kj/mol Enthalpy of atomization of fluorine = +79kj/mol 1st ionization energy of pottasium = +418kj/mol Electron affinity of fluorine = -328kj/mol Enthalpy of formation of potassium fluoride = -561.7kj/mol
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.
1. An 800g aluminium block cools from 85°C to 30 °C. Calculate the heat capacity, C, of the aluminium block.
2. Construct an energy cycle diagram for potassium fluoride.
3. Determine the lattice energy of potassium fluoride.
Enthalpy of atomization of potassium = +89.2kj/mol
Enthalpy of atomization of fluorine = +79kj/mol
1st ionization energy of pottasium = +418kj/mol
Enthalpy of formation of potassium fluoride = -561.7kj/mol
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