||| Identifying phase transitions on a heating curve A pure solid sample of Substance X is put into an evacuated flask. The flask is heated at a steady rate and the temperature recorded as time passes. Here is graph of the results: temperature (°C) 80. 60. Explanation 40. 20. Use this graph to answer the following questions: What is the melting point of X? heat added (kJ/mol) Check °C (check all that annly) 4/5 ©2023 McGraw Hill All Rights Reserved Terms of Use | Privacy Contor I
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.
Melting point is the temperature at which a solid substance changes state from a solid to a liquid. It is the temperature at which the substance's solid state becomes unstable, and the molecules within the solid begin to move more rapidly, eventually breaking free from their fixed positions and transitioning into a liquid state.
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