Advice 1: How to determine the equivalent substances

Equivalent substances are simulated or real particle, which can release, attach or in any way be equivalent to hydrogen cations participating in ion-exchange reactions, or electron in redox reactions. When solving problems under the equivalent of a substance is equivalent to a mean molar mass of the substance.
How to determine the equivalent substances
You will need
  • is the molar mass;
  • - the valence;
  • - acidity;
  • - basicity.
The equivalentprobability weight is one of the most important characteristics of substances. When solving problems it is denoted as M EQ. Is determined by the molar equivalent weight of any compound, the chemical formula of the studied substances and its belonging to a particular class of chemical compounds.
In order to find the molar mass equivalents, you'll need to know such factors as molar mass – the mass of one mole of a substance. The basicity of acids the number of hydrogen atoms that the acid can attach. The acidity of the base is determined by the number of OH-ions. Valence – the number of chemical bonds that an atom forms with other elements in the mix.
The formula for finding the equivalent mass of a substance depends on what class applies the test compound. For example, for finding the equivalent substances of the oxides, you will need to divide molar mass of compound by the number of oxygen atoms, is pre-multiplied by two. For example, for Fe2O3 equivalent weight is equal to 56*2 + 16*3/3*2 = 26,7 g/mol.
To find the molar mass of the equivalent substances at the base, divide the molar mass of the base in its acidity. So, for the base Ca(OH)2 equivalent will be equal to 40 + (16+2)*2/2 = 37 g/mol.
To find equivalent substances for the acid, you will need to do the following: divide the molar mass of the acid is its basicity. To find the molar mass of equivalent of the substance sulfuric acid, H2SO4 divide 1*2 + 32 + 16*4/2 = 49 g/mol.
Finally, to find equivalent substances of salt, divide the molar mass of the substance by the number of metal atoms, multiplied by its valence. For example, the molar mass equivalent substances salts Al2(SO4)3 = 27*2 + (32 + 16*4)*3/1*2 = 171 g/mol.

Advice 2 : How to find the equivalent mass of

The chemical elements are connected to each other in strictly defined proportions. That is why there was such a thing as equivalent and equivalent weight. ("Equivalent" literally means "equal", "equivalent"). What is the equivalent in the chemical sense of the word? How to calculate the equivalent (or equivalent mass?
How to find the equivalent mass of
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.
Useful advice
Currently under the equivalent item made to understand this quantity, which is connected with one mole of hydrogen atoms or replaces the same number of hydrogen atoms in chemical reactions. The mass of one equivalent of an element is called its equivalent weight.
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