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An endothermic process is a chemical or physical process that absorbs heat from its surroundings. [1] In terms of thermodynamics, it is a thermodynamic process with an increase in the enthalpy H (or internal energy U) of the system. [2] In an endothermic process, the heat that a system absorbs is thermal energy transfer into the
In thermochemistry, a thermochemical equation is a balanced chemical equation that represents the energy changes from a system to its surroundings.One such equation involves the enthalpy change, which is denoted with In variable form, a thermochemical equation would appear similar to the following:
The enthalpy of solution is most often expressed in kJ/mol at constant temperature. The energy change can be regarded as being made up of three parts: the endothermic breaking of bonds within the solute and within the solvent, and the formation of attractions between the solute and the solvent. An ideal solution has a null enthalpy of mixing.
The law states that the total enthalpy change during the complete course of a chemical reaction is independent of the sequence of steps taken. [2] [3] Hess's law is now understood as an expression of the fact that the enthalpy of a chemical process is independent of the path taken from the initial to the final state (i.e. enthalpy is a state ...
Endothermic reactions absorb heat, while exothermic reactions release heat. Thermochemistry coalesces the concepts of thermodynamics with the concept of energy in the form of chemical bonds. The subject commonly includes calculations of such quantities as heat capacity, heat of combustion, heat of formation, enthalpy, entropy, and free energy.
Thus, they are essentially equations of state, and using the fundamental equations, experimental data can be used to determine sought-after quantities like G (Gibbs free energy) or H . [1] The relation is generally expressed as a microscopic change in internal energy in terms of microscopic changes in entropy , and volume for a closed system in ...
The Van 't Hoff equation relates the change in the equilibrium constant, K eq, of a chemical reaction to the change in temperature, T, given the standard enthalpy change, Δ r H ⊖, for the process. The subscript r {\displaystyle r} means "reaction" and the superscript ⊖ {\displaystyle \ominus } means "standard".
In the thermodynamics of equilibrium, a state function, function of state, or point function for a thermodynamic system is a mathematical function relating several state variables or state quantities (that describe equilibrium states of a system) that depend only on the current equilibrium thermodynamic state of the system [1] (e.g. gas, liquid, solid, crystal, or emulsion), not the path which ...