Can a chemical be introduced to a volume of water which can actually reduce the volume of water in that container?


marked as duplicate by Todd Minehardt, Geoff Hutchison, bon, Jan, Jannis Andreska Sep 28 '15 at 12:59

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Yes, at least if only the total volume should decrease:

Density of water: $1000~\mathrm{kg/m^3}$
Density of ethanol: $789~\mathrm{kg/m^3}$
Expected density of 52 Vol.% ethanol solution: $890~\mathrm{kg/m^3}$
True density of 52 Vol.% ethanol solution: $909~\mathrm{kg/m^3}$
All values are for the same conditions.

The volume of every ethanol-water-solution is smaller than the sum of the original volumes of water and ethanol. For example if you add 52 mL of ethanol to 48 mL water you will get a solution with an volume of approximately 97,9 mL.
This is effect is known as volume contraction and depends on the mixing ratio of both components in a nonlinear way. Its reason is the formation of additional bonding forces (e. g. hydrogen briges) between the molecules, which results in a higher denisty.

Note: I don´t think that there is something that can increase density of water in such a way, that the resulting volume is actually smaller than the water's volume.


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