The entropy of mixing (\(\Delta S_{\text{mix}}\)) is the increase in total entropy that occurs when two or more distinct chemical substances or systems mix together spontaneously without a chemical reaction.
Core Formula (Ideal Mixtures)
For an ideal mixture or ideal gases, the entropy of mixing is always positive (\(\Delta S_{\text{mix}} > 0\)), reflecting the spontaneous, irreversible nature of diffusion and increased spatial/positional uncertainty:
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