Born-Haber cycle is a cycle of reactions used for calculating the lattice energies of ionic crystalline solids. For a compound MX, the lattice energy is the enthalpy of the reaction
The standard enthalpy of formation of the ionic solid is the enthalpy of the reaction
The cycle involves equating this enthalpy (which can be measured) to the sum of the enthalpies of a number of steps proceeding from the elements to the ionic solid. The steps are:
1) Atomization of the metal
2) Atomization of the nonmetal
3) Ionisation of the metal
This is obtained from the ionisation potential.
4) Ionisation of the nonmetal
This is electron affinity.
5) Formation of the ionic solids
Equation of the enthalpies gives
from which ΔHL can be found.
Covalentity is a maximum number of covalent bond that one atom can make, it is equal to the number of hydrogen atoms that are combined with other atoms. It is usually constant.
Electron spin (s) is the quantum number, equal to 1/2, that specifies the intrinsic angular momentum of the electron.
Electron volt (eV) is a non-SI unit of energy used in atomic and nuclear physics, equal to approximately 1.602 177×10-19 J. The electron volt is defined as the kinetic energy acquired by an electron upon acceleration through a potential difference of 1 V.
For value of zero in Celsius temperature scale the freezing point of water at a pressure of 101 325 Pa is taken. The boiling point of water at a pressure of 101 325 Pa is taken as another reference point. This range is divided into 100 equal parts, and each part is an equivalent to 1 °C. Units of Celsius temperature scale (°C) and thermodynamic temperature scale (K) are identical
1 °C = 1 K.
The volume of a fixed mass of gas at a constant pressure expand by the constant fraction of its volume at 0 °C. For each Celsius or kelvin degree its temperature is raised. For any ideal gas fraction it is approximately 1/273. This can be expressed by the equation
were V° is the volume at 0°C and V is its volume at t°C.
This is equivalent to the statement that the volume of a fixed mass of gas at a constant pressure is proportional to its thermodynamic temperature
This law also know as Gay-Lussac’s law.
An equation similar to the one given above applies to pressures for ideal gases:
Elementary reaction is a reaction that occurs in a single step. Equations for elementary reactions show the actual molecules, atoms, and ions that react on a molecular level.
Generalic, Eni. "Equal-arm balance." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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