Equivalents and equivalent mass are usually determined either according to the analysis of compounds or on the basis of the results of the substitution of one element with another. It is easy to understand that to determine equivalent (or equivalent mass) of an element does not necessarily come from its compounds with hydrogen. The equivalent (equivalent mass) can similarly compute the compound of this element with any other, equivalent (equivalent mass) is known.
Example. When connecting 1.50 grams of sodium with excess chlorine formed 3.81 grams of sodium chloride. You need to find the equivalent mass of sodium and its equivalent, if it is known that the equivalent weight of chlorine is equal to 35,45 g/mol.Solution. Subtract from the total mass of the formed product of the original mass of sodium.
Thus, 3, 81 – 1, 50 = 2, 31
That is, in the formed product (in your case sodium chloride) 1.50 grams of sodium accounts for 2.31 grams of chlorine. From this it follows that knowing the equivalent weight of chlorine (35, 45 gram/mol), you can easily find the equivalent mass of sodium by the following formula:
35, 45 x 1, 50 / 2, 31 is the Equivalent mass of sodium is equal to 23,0 g/mol.
Molar mass of sodium will also be equal to 23,0 g/mol. From this it follows that the equivalent of sodium is equal to one pray (as the molar equivalent weight of sodium is the same).
The concept of equivalents and equivalent masses also apply to complex substances. The equivalent complex substance called this number that communicates without residue with one equivalent of hydrogen.