The calculation of standard absolute entropy values, S₂₉₈^o, of salt hydrates from their molecular volumes is reconsidered. The major effect on the entropy comes from the number of water molecules in the hydrated salt. Values of S₂₉₈^o for 12 salt hydrates and 9 anhydrous salts not previously reported are presented.

中文翻译：

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盐水合物的标准绝对熵S ₂₉₈ ^o（根据体积和水合物数）以及热力学差异规则

重新考虑从盐水合物的分子体积计算标准绝对熵值S ₂₉₈ ^o。对熵的主要影响来自于水合盐中水分子的数量。给出了先前未报道的12种盐水合物和9种无水盐的S ₂₉₈ ^o值。