you need
• - the molar mass;
• - the valence;
• - acidity;
• - mostly.
Guide
1
equivalent mass of one of the most important characteristics of substances.When solving problems, it is designated as M eq.Determined molar mass equivalent of a compound based on the chemical formula of the test substance and his belonging to a particular class of chemical compounds.
2
In order to successfully find the molar mass equivalents, you need to know such factors as the molar mass - the mass of one mole of substance .Basicity acid - hydrogen atoms, which acid may attach.The acidity of the base determined by the number of ions OH-.Valence - the number of chemical bonds, which forms the atom wi
th the other elements in the mix.
3
formula for finding the equivalent weight of a substance depends on what class is the test compound.For example, to find the equivalent substance oxides have, you will need to divide the molar mass of the compound to the number of atoms of oxygen, pre-multiplied by two.For example, for iron oxide Fe2O3 equivalent weight is equal to 56 * 2 + 16 * 3/3 * 2 = 26.7 g / mol.
4
To find the molar mass equivalent substance at the base, divide the molar mass of the base on its acidity.So, for the foundation of Ca (OH) 2 will be the equivalent of 40 + (16 + 2) * 2/2 = 37 g / mol.
5
To find the equivalent of substance to acid, you will need to do the following: divide the molar mass of the acid on its core.To find the molar mass equivalent substance sulfuric acid H2SO4 divide 1 * 2 + 32 + 16 * 4/2 = 49 g / mol.
6
Finally, to find the equivalent substance salt divide the molar mass of the substance the number of metal atoms, multiplied by its valence.For example, the molar mass of equivalent substance salt Al2 (SO4) 3 * 2 = 27 + (32 + 16 * 4) * 3/1 * 2 = 171 g / mol.