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- https://chem.libretexts.org/Courses/Nassau_Community_College/General_Chemistry_1/09%3A_Thermochemistry/9.04%3A_EnthalpyIf a chemical change is carried out at constant pressure and the only work done is caused by expansion or contraction, q for the change is called the enthalpy change with the symbol ΔH. Examples of en...If a chemical change is carried out at constant pressure and the only work done is caused by expansion or contraction, q for the change is called the enthalpy change with the symbol ΔH. Examples of enthalpy changes include enthalpy of combustion, enthalpy of fusion, enthalpy of vaporization, and standard enthalpy of formation. If the enthalpies of formation are available for the reactants and products of a reaction, the enthalpy change can be calculated using Hess’s law.
- https://chem.libretexts.org/Courses/Western_Washington_University/Biophysical_Chemistry_(Smirnov_and_McCarty)/01%3A_Biochemical_Thermodynamics/1.03%3A_ThermochemistryIn this chapter we apply the first law of thermodynamics and the concept of enthalpy introduced in Chapter I.2 to chemical reactions. At standard state conditions we can use tabulated heats of formati...In this chapter we apply the first law of thermodynamics and the concept of enthalpy introduced in Chapter I.2 to chemical reactions. At standard state conditions we can use tabulated heats of formation to calculate the change in enthalpy for any reaction. At temperatures other than standard conditions we use the temperature dependence of the enthalpy to derive an expression for the change in enthalpy of a reaction at any temperature in relation to a reference temperature.
- https://chem.libretexts.org/Courses/University_of_North_Carolina_Charlotte/CHEM_2141%3A__Survey_of_Physical_Chemistry/02%3A_General_Chemistry_Review/2.02%3A_Thermodynamics/2.2.02%3A_EnthalpyIf a chemical change is carried out at constant pressure and the only work done is caused by expansion or contraction, q for the change is called the enthalpy change with the symbol ΔH. Examples of en...If a chemical change is carried out at constant pressure and the only work done is caused by expansion or contraction, q for the change is called the enthalpy change with the symbol ΔH. Examples of enthalpy changes include enthalpy of combustion, enthalpy of fusion, enthalpy of vaporization, and standard enthalpy of formation. If the enthalpies of formation are available for the reactants and products of a reaction, the enthalpy change can be calculated using Hess’s law.
- https://chem.libretexts.org/Courses/Williams_School/Chemistry_IIA/02%3A_Thermochemistry/2.02%3A_The_First_Law_of_ThermodynamicsThe first law of thermodynamics states that the energy of the universe is constant. The change in the internal energy of a system is the sum of the heat transferred and the work done. At constant pres...The first law of thermodynamics states that the energy of the universe is constant. The change in the internal energy of a system is the sum of the heat transferred and the work done. At constant pressure, heat flow (q) and internal energy (U) are related to the system’s enthalpy (H). The heat flow is equal to the change in the internal energy.
- https://chem.libretexts.org/Courses/Widener_University/CHEM_145%3A_FA22_Van_Bramer/06%3A_Thermochemistry/6.06%3A_EnthalpyIf a chemical change is carried out at constant pressure and the only work done is caused by expansion or contraction, q for the change is called the enthalpy change with the symbol ΔH. Examples of en...If a chemical change is carried out at constant pressure and the only work done is caused by expansion or contraction, q for the change is called the enthalpy change with the symbol ΔH. Examples of enthalpy changes include enthalpy of combustion, enthalpy of fusion, enthalpy of vaporization, and standard enthalpy of formation. If the enthalpies of formation are available for the reactants and products of a reaction, the enthalpy change can be calculated using Hess’s law.
- https://chem.libretexts.org/Courses/Widener_University/Widener_University%3A_Chem_135/06%3A_Thermochemistry/6.03%3A_Enthalpy-_IntroductionIf a chemical change is carried out at constant pressure and the only work done is caused by expansion or contraction, q for the change is called the enthalpy change with the symbol ΔH. Examples of en...If a chemical change is carried out at constant pressure and the only work done is caused by expansion or contraction, q for the change is called the enthalpy change with the symbol ΔH. Examples of enthalpy changes include enthalpy of combustion, enthalpy of fusion, enthalpy of vaporization, and standard enthalpy of formation. If the enthalpies of formation are available for the reactants and products of a reaction, the enthalpy change can be calculated using Hess’s law.
- https://chem.libretexts.org/Courses/Widener_University/Widener_University%3A_Chem_135/06%3A_Thermochemistry/6.04%3A_Enthalpy-_Heat_of_CombustionIf a chemical change is carried out at constant pressure and the only work done is caused by expansion or contraction, q for the change is called the enthalpy change with the symbol ΔH. Examples of en...If a chemical change is carried out at constant pressure and the only work done is caused by expansion or contraction, q for the change is called the enthalpy change with the symbol ΔH. Examples of enthalpy changes include enthalpy of combustion, enthalpy of fusion, enthalpy of vaporization, and standard enthalpy of formation. If the enthalpies of formation are available for the reactants and products of a reaction, the enthalpy change can be calculated using Hess’s law.
- https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Physical_Chemistry_(Fleming)/01%3A_The_Basics/1.01%3A_The_System_and_the_SurroundingsThe page discusses the Zeroth Law of Thermodynamics, emphasizing the importance of defining key terms like "system" and "surroundings." Various types of systems are identified, such as open, closed, a...The page discusses the Zeroth Law of Thermodynamics, emphasizing the importance of defining key terms like "system" and "surroundings." Various types of systems are identified, such as open, closed, and isolated systems, based on how they allow matter and energy transfer. The distinctions between homogeneous and heterogeneous systems are also outlined, along with the significance of intensive and extensive variables.
- https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Physical_Chemistry_(Fleming)/05%3A_The_Second_Law/5.03%3A_EntropyThe page discusses the Carnot engine and its relationship with temperature and efficiency. It explains how the total heat transferred in the cycle is derived, showing that heat (q) is not a state func...The page discusses the Carnot engine and its relationship with temperature and efficiency. It explains how the total heat transferred in the cycle is derived, showing that heat (q) is not a state function due to its net change around a closed cycle being non-zero. However, when considering the sum of q/T, it results in zero, which aligns with the behavior of a state function.
- https://chem.libretexts.org/Courses/San_Francisco_State_University/General_Physical_Chemistry_I_(Gerber)/05%3A_Entropy_and_The_Second_Law_of_Thermodynamics/5.03%3A_Unlike_heat_Entropy_is_a_State_FunctionEntropy, S, is a state function, so it does not depend on the thermodynamic path. We can take any path we want to calculate the entropy of a thermodynamic system.
- https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Thermodynamics/Fundamentals_of_Thermodynamics/State_vs._Path_FunctionsA state function is a property whose value does not depend on the path taken to reach that specific value. In contrast, functions that depend on the path from two values are call path functions. Both ...A state function is a property whose value does not depend on the path taken to reach that specific value. In contrast, functions that depend on the path from two values are call path functions. Both path and state functions are often encountered in thermodynamics.
