|
Explanation... |
When an aqueous solution of an ionic compound is dried
out, most of the water evaporates and leaves the container. Some
of the water molecules stay behind, attached to the solid ionic crystal.
This type of compound is called a hydrate.
|
|
Rules for Writing Formulas of Hydrates |
| Rule 1: Include the water at the end of
the formula. There is a dot separating the regular compound
formula and the water. Rule 2: Put a number after the dot
and before the H2O to indicate how many water molecules are
associated with the compound.
|
|
Rules for Writing Names of Hydrates |
| Rule 1: Name the regular part of the
compound as usual. Rule 2: After the regular compound
name, put the word "hydrate". Rule 3: Use a number
prefix in front of "hydrate" to show how many water molecules are
associated with the compound.
| 1 = mono |
|
6 = hexa |
| 2 = di |
|
7 = hepta |
| 3 = tri |
|
8 = octa |
| 4 = tetra |
|
9 = nona |
| 5 = penta |
|
10 = deca |
|
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Examples... |
| Cu(BrO3)2·6H2O |
copper(II) bromate hexahydrate |
| CoC2O4·2H2O |
cobalt(II) oxalate dihydrate |
| FeI2·4H2O |
iron(II) iodide tetrahydrate |
| Au(CN)3·3H2O |
gold(III) cyanide trihydrate |
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