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MnCl 2 + 2 NaC 5 H 5 → Mn(C 5 H 5) 2 + 2 NaCl. Similar reactions are used in the preparation of the antiknock compound methylcyclopentadienyl manganese tricarbonyl. [3] Manganese chloride is a precursor to organomanganese reagents in organic chemistry. [7] [8] Manganese chloride is mainly used in the production of dry cell batteries.
The gas constant occurs in the ideal gas law: = = where P is the absolute pressure, V is the volume of gas, n is the amount of substance, m is the mass, and T is the thermodynamic temperature. R specific is the mass-specific gas constant. The gas constant is expressed in the same unit as molar heat.
molar mass of carbon-12: 12.000 000 0126 (37) × 10 −3 kg⋅mol −1: 3.1 × 10 −10 [53] = / atomic mass constant: 1.660 539 068 92 (52) × 10 −27 kg: 3.1 × 10 −10 [54] = / molar mass constant: 1.000 000 001 05 (31) × 10 −3 kg⋅mol −1: 3.1 × 10 −10 [55]
where P is the pressure, V is volume, n is the number of moles, R is the universal gas constant and T is the absolute temperature. The proportionality constant, now named R, is the universal gas constant with a value of 8.3144598 (kPa∙L)/(mol∙K). An equivalent formulation of this law is: =
The molar mass constant, usually denoted by M u, is a physical constant defined as one twelfth of the molar mass of carbon-12: M u = M(12 C)/12. [1] The molar mass of an element or compound is its relative atomic mass (atomic weight) or relative molecular mass (molecular weight or formula weight) multiplied by the molar mass constant.
The molar mass of atoms of an element is given by the relative atomic mass of the element multiplied by the molar mass constant, M u ≈ 1.000 000 × 10 −3 kg/mol ≈ 1 g/mol. For normal samples from Earth with typical isotope composition, the atomic weight can be approximated by the standard atomic weight [ 2 ] or the conventional atomic weight.
An equivalent statement of the Dulong–Petit law in modern terms is that, regardless of the nature of the substance, the specific heat capacity c of a solid element (measured in joule per kelvin per kilogram) is equal to 3R/M, where R is the gas constant (measured in joule per kelvin per mole) and M is the molar mass (measured in kilogram per mole).
Substituting from the ideal gas equation gives finally: = where n = number of moles of gas in the thermodynamic system under consideration and R = universal gas constant. On a per mole basis, the expression for difference in molar heat capacities becomes simply R for ideal gases as follows: