Chemical calculations theory
Chemical calculations theory. Matter and its transformations.
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.
Percentage composition of a substance:
Deduction of formulas from the percentage composition:
(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:
(a = mass, in grams, of the substance, M = molecular mass of the substance)
Electric charge of 1 mole of electrons:
(F = faraday electricity = 96500 C; No = Avogadro’s number, e = electron charge = 1.6 ·10-19C)
(A = atomic mass of the element; M = molecular mass of the compound; val = valence)
(A = atomic mass of the solid element; Ce = specific heat of solid element)
You can download the App BioProfe READER to practice this theory with self-corrected exercises.