The criteria for equilibrium and spontaneity are closely related to the concept of Gibbs free energy, which is a thermodynamic function that measures the energy available in a system to do useful work. The Gibbs free energy is defined as follows: ΔG = ΔH – TΔS where ΔG is the change in Gibbs free energy,…
Gibbs energy, also known as Gibbs free energy, is a thermodynamic quantity that measures the amount of energy available to do useful work in a chemical reaction or physical process at constant temperature and pressure. It is denoted by the symbol G and has units of joules (J) or kilojoules (kJ) per mole. Gibbs energy…
Entropy is a concept from thermodynamics that refers to the degree of disorder or randomness in a system. In statistical mechanics, it is often defined as the number of microstates (arrangements of particles or energy levels) that correspond to a given macrostate (observable properties like temperature, pressure, or volume). The greater the number of microstates,…
The second law of thermodynamics is a fundamental principle in physics that states that in any spontaneous process, the total entropy of a closed system will always increase over time, or remain constant in ideal cases. Entropy is a measure of the disorder or randomness of a system, and the second law of thermodynamics tells…
Lattice enthalpy is a measure of the energy required to separate the ions in a solid ionic compound to an infinite distance from each other. It is a type of enthalpy of dissociation and is a measure of the strength of the ionic bonds in the compound. Lattice enthalpy is a negative quantity, which means…
Fusion and vaporization are two different physical processes that involve changing the state of matter. Fusion, also known as melting, is the process by which a solid substance is transformed into a liquid as a result of heat being applied to it. The heat energy causes the molecules of the solid to vibrate more rapidly,…
The enthalpy of reaction (ΔHrxn) is the amount of heat released or absorbed during a chemical reaction at a constant pressure. It represents the change in the enthalpy of the system as reactants are transformed into products. If the enthalpy of reaction is negative (ΔHrxn < 0), it means that the reaction is exothermic, and…
Hess’s law is a fundamental principle in chemistry that states that the total enthalpy change of a chemical reaction is independent of the pathway between the initial and final states. In other words, if a reaction can occur by multiple paths, the change in enthalpy will be the same regardless of the specific path taken.…
The standard state of a substance is a reference state used in thermodynamics, which is typically defined as the most stable physical state of the substance at a pressure of 1 bar and a specified temperature, usually 25°C (298.15 K). For pure substances, the standard state is often the most common state of the substance…
Heat capacity is the amount of heat energy required to raise the temperature of a substance by one degree Celsius or one Kelvin. It is a physical property of a substance that measures its ability to store heat energy. Heat capacity is usually denoted by the symbol “C” and has units of joules per degree…
