The law of definite proportions would state that a hydrate always contain exactly the same proportion of salt and water by mass. strictly speaking, the law of definite proportion states that a compound always contains exactly the same proportion of elements by mass. But the law is often applied to groupings of elements in compound. Hydrates are salt that have a certain amount of water asa part of their structure. The water is chemically combined with the compound in a definite ratio.
The law of definite proportions, which states that a compound will always contain the same proportions of elements by mass , applies to hydrates as well. This holds true for both liquid and ionic hydrates , which always maintain a set ratio of constituent elements. ;
The law of definite proportions states that in any chemical compound, elements combine in the same mass proportions. This applies to hydrates as well, as the mass ratio of water to the ionic compound remains constant in any given hydrate. For example, in copper(II) sulfate pentahydrate, the ratio of CuSO₄ to its five water molecules is invariant.
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