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Enthalpies of melting and boiling for pure elements versus temperatures of transition, demonstrating Trouton's rule. In thermodynamics, the enthalpy of fusion of a substance, also known as (latent) heat of fusion, is the change in its enthalpy resulting from providing energy, typically heat, to a specific quantity of the substance to change its state from a solid to a liquid, at constant pressure.
10 1: daM 17.5 M pure (glacial) acetic acid (1.05 g/cm 3) [22] 40 M: pure solid hydrogen (86 g/L) [23] 55.5 M: pure water at 3.984 °C, temperature of its maximum density (1.0000 g/cm 3) [24] 10 2: hM 118.8 M: pure osmium at 20 °C (22.587 g/cm 3) [25] 140.5 M: pure copper at 25 °C (8.93 g/cm 3) 10 3: kM: 10 4: 24 kM: helium in the solar core ...
The SI unit of molar absorption coefficient is the square metre per mole (m 2 /mol), but in practice, quantities are usually expressed in terms of M −1 ⋅cm −1 or L⋅mol −1 ⋅cm −1 (the latter two units are both equal to 0.1 m 2 /mol). In older literature, the cm 2 /mol is sometimes used; 1 M −1 ⋅cm −1 equals 1000 cm 2 /mol.
Since 1 mole = 6.02214076 × 10 23 particles (atoms, molecules, ions etc.), 1 joule per mole is equal to 1 joule divided by 6.02214076 × 10 23 particles, ≈1.660539 × 10 −24 joule per particle. This very small amount of energy is often expressed in terms of an even larger unit such as the kJ·mol −1 , because of the typical order of ...
It was originally defined as "the quantity or mass of radium emanation in equilibrium with one gram of radium (element)", [1] but is currently defined as 1 Ci = 3.7 × 10 10 decays per second [4] after more accurate measurements of the activity of 226 Ra (which has a specific activity of 3.66 × 10 10 Bq/g [5]).
Normality is defined as the number of gram or mole equivalents of solute present in one liter of solution.The SI unit of normality is equivalents per liter (Eq/L). = where N is normality, m sol is the mass of solute in grams, EW sol is the equivalent weight of solute, and V soln is the volume of the entire solution in liters.
Atmospheric pollutant concentrations expressed as mass per unit volume of atmospheric air (e.g., mg/m 3, μg/m 3, etc.) at sea level will decrease with increasing altitude because the atmospheric pressure decreases with increasing altitude. The change of atmospheric pressure with altitude can be obtained from this equation: [2]
A closely related property of a substance is the heat capacity per mole of atoms, or atom-molar heat capacity, in which the heat capacity of the sample is divided by the number of moles of atoms instead of moles of molecules. So, for example, the atom-molar heat capacity of water is 1/3 of its molar heat capacity, namely 25.3 J⋅K −1 ⋅mol ...