|What chemical properties of water cause it to be a medium of life? — WZ, Pacific Palisades, CA
Water is such a remarkable chemical that I hardly know where to begin. First, it is one of the lightest, simplest molecules and yet it remains a liquid even at temperatures approaching 100° C, making it well suited as a medium for chemistry of all sorts. Second, it is an extremely good solvent for a vast range of ionic and organic materials, so that it is an ideal medium for the complicated chemical mixtures of biology. Third, water has enormous latent heats of melting and vaporization that make it hard to freeze and its evaporation very effective at cooling a hot animal.