# Chemical calculations theory. Matter and its transformations.

Chemical calculations

Mole concept: Mol is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kg of carbon 12.

Relationship between mole and atomic or molecular mass: The mass of 1 mole of any substance (simple or compound), expressed in grams, coincides with the numerical value of its atomic or molecular mass.

Avogadro’s Number: The number of elementary entities in one mole of any substance: No = 6.022 · 1023 mol -1.

Molar volume of a gas normally, Vmn: is the volume occupied by 1 mole of any gas, measured at normal conditions (0ºC and 1 atm), Vmn = 22.4 L / mol.

Equivalent weight of an element or compound, also called chemical equivalent, Peq: is the amount that is combined or replaced (chemically equivalent) to 1.008 parts of hydrogen.

FORMULA SUMMARY

Percentage composition of a substance: Bioprofe |Chemical calculations theory| 01

Deduction of formulas from the percentage composition: Bioprofe |Chemical calculations theory| 02

(A = atomic mass of the element; M = molecular mass of the compound)

Relationship between the number of moles and the mass in grams of a substance: Bioprofe |Chemical calculations theory| 03

(a = mass, in grams, of the substance, M = molecular mass of the substance)

Electric charge of 1 mole of electrons: Bioprofe |Chemical calculations theory| 04

(F = faraday electricity = 96500 C; No = Avogadro’s number, e = electron charge = 1.6 ·10-19C)

Equivalent weight: Bioprofe |Chemical calculations theory| 05

(A = atomic mass of the element; M = molecular mass of the compound; val = valence)

Dulong-Petit law: Bioprofe |Chemical calculations theory| 06

(A = atomic mass of the solid element; Ce = specific heat of solid element)