Guide

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First, we should remember a few simple rules.If it is a metal, its equivalent weight is calculated as follows: Mae = M / V, where M - the atomic mass of metal

**, and B - its valence.Consider this rule to specific examples.** 2

Calcium (Ca).Its atomic weight 40.08.Rounded take it for 40. The valence is 2. Therefore, Mae (Ca) = 40/2 = 20 g / mol.Aluminum (Al).Its atomic weight 26.98.(Rounding 27).Valency is 3. Thus, Mae (Al) = 27/3 = 9 g / mol.

3

These methods are applicable, if it is a pure metal

**'s.And if they are part of a compound, such as oxides of the same?Here we must remember another rule: the equivalent weight****oxide is calculated as follows: + Mae Mo, where Mo - equivalent weight of oxygen.It is, accordingly, calculated according to the formula already considered the M / B, ie 16/2 = 8.** 4

Suppose you have a basic aluminum oxide, Al2O3.How to calculate its equivalent weight?Very simple: 27/3 + 16/2 = 17 g / mol.

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Is there any other way to determine the equivalent weight

**metal and oxide****?Yes, and very effective.It is based on the so-called law equivalents, whereby all substances react with each other in equivalent amounts.For example, the metal mass of 33.4 grams reacted oxidation with atmospheric oxygen.The result is an oxide of a total weight of 43 grams.It is required to determine the equivalent weight***of***metal and oxide****.** 6

first calculate how much oxygen is united with the metal in the course of the reaction: 43 - 33.4 = 9.6 grams.According to the law of equivalents, the weight as many times more than the equivalent weight

*oxygen (which, recall, is 8), how many times the equivalent weight of metal***less than the original amount.That is 33.4 / Mae (IU) = 9.6 / 8.Consequently, Mae (IU) = 33.4 * 8 / 9.6 = 27.833 g / mol, or rounded 27.8 g / mole.This is the equivalent weight of metal****.** 7

The equivalent weight of the oxide

**find the following: 27.8 + 8 = 35.8 g / mol.**