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Some chemistry textbooks [3] as well as the widely used CRC Handbook of Chemistry and Physics [4] define lattice energy with the opposite sign, i.e. as the energy required to convert the crystal into infinitely separated gaseous ions in vacuum, an endothermic process. Following this convention, the lattice energy of NaCl would be +786 kJ/mol.
The calculated lattice energy gives a good estimation for the Born–Landé equation; the real value differs in most cases by less than 5%. Furthermore, one is able to determine the ionic radii (or more properly, the thermochemical radius) using the Kapustinskii equation when the lattice energy is known.
The polarized form of the water molecule, H + OH −, is also called hydron hydroxide by IUPAC nomenclature. [106] Water substance is a rare term used for H 2 O when one does not wish to specify the phase of matter (liquid water, water vapor, some form of ice, or a component in a mixture) though the term "water" is also used with this general ...
Free protons of high energy and velocity make up 90% of cosmic rays, which propagate through the interstellar medium. [33] Free protons are emitted directly from atomic nuclei in some rare types of radioactive decay. [34] Protons also result (along with electrons and antineutrinos) from the radioactive decay of free neutrons, which are unstable ...
The macroscopic energy equation for infinitesimal volume used in heat transfer analysis is [6] = +, ˙, where q is heat flux vector, −ρc p (∂T/∂t) is temporal change of internal energy (ρ is density, c p is specific heat capacity at constant pressure, T is temperature and t is time), and ˙ is the energy conversion to and from thermal ...
The Born–Landé equation is a means of calculating the lattice energy of a crystalline ionic compound.In 1918 [1] Max Born and Alfred Landé proposed that the lattice energy could be derived from the electrostatic potential of the ionic lattice and a repulsive potential energy term.
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...
z + = charge number of cation; z − = charge number of anion; e = elementary charge, 1.6022 × 10 −19 C; ε 0 = permittivity of free space 4 π ε 0 = 1.112 × 10 −10 C 2 /(J·m) r 0 = distance to closest ion; ρ = a constant dependent on the compressibility of the crystal; 30 pm works well for all alkali metal halides