equivalent

[americanpierg]

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Can anyone explain equivalent to me?

Equivalents = weight of compound/ gram equivalent weight
gram equivalent weight = molar mass / n
n = number of hydrogens or hydroxyl groups used per molecule of acid or base used in a reaction, respectively

this doesnt make any sense to me logically. anyone care to explain?

 

[UCB05]

reactants don't always work on a 1-molecule-1-reaction basis. Sulfuric acid can donate 2 protons per molecule, so one mol of H2SO4 reacts as if there's 2 mols of monoprotic acid. So for that acid, 1 mol acid reacts as 2 equivalents of protons. gram equivalents just means converting the mols to grams. 1 equivalent of H2SO4 in an acid-base reaction is actually just half a mol of H2SO4, or half the MM. H3PO4 has 3 equivalents of protons so its gram equivalent mass to get just one equivalent of protons is MM/3.

This also works for colligative properties (one molecule of NaCl is worth 2 equivalents of ions) and other reactions (MgCl2 provides 2 equivalents of chloride ions).

To know what equivalents to look for you have to know the reaction in question to begin with. H2SO4 provides one equivalent of sulfate ions for substitutions, 2 equivalents of protons for acid/base reactions, 3 equivalents of ions for solubilities, etc.

 

[americanpierg]

reactants don't always work on a 1-molecule-1-reaction basis. Sulfuric acid can donate 2 protons per molecule, so one mol of H2SO4 reacts as if there's 2 mols of monoprotic acid. So for that acid, 1 mol acid reacts as 2 equivalents of protons. gram equivalents just means converting the mols to grams. 1 equivalent of H2SO4 in an acid-base reaction is actually just half a mol of H2SO4, or half the MM. H3PO4 has 3 equivalents of protons so its gram equivalent mass to get just one equivalent of protons is MM/3.

This also works for colligative properties (one molecule of NaCl is worth 2 equivalents of ions) and other reactions (MgCl2 provides 2 equivalents of chloride ions).

To know what equivalents to look for you have to know the reaction in question to begin with. H2SO4 provides one equivalent of sulfate ions for substitutions, 2 equivalents of protons for acid/base reactions, 3 equivalents of ions for solubilities, etc.

lol...sorry im ******ed. I didnt bother to plug in numbers into the equation and see that weight of compound/ gram equivalent weight is just n.