molar volume
molar volume,
the volume occupied by a molemole,in chemistry, a quantity of particles of any type equal to Avogadro's number, or 6.02×1023 particles. One gram-molecular weight of any molecular substance contains exactly one mole of molecules.
..... Click the link for more information. of a substance at STPSTP
or standard temperature and pressure,
standard conditions for measurement of the properties of matter. The standard temperature is the freezing point of pure water, 0°C; or 273.15°K;.
..... Click the link for more information. . According to Avogadro's law, at a given temperature and pressure a given volume of any gas contains the same number of molecules. At STP 1 mole of gas occupies 22.414 liters. This volume is what is usually meant by the molar volume, although one can also speak of molar volumes of substances that are not gaseous at STP. Since at STP water occupies very nearly 1 cc per gram, and since 1 mole of water molecules weighs very nearly 18 grams, the molar volume of water is about 18 cc. The molar volume of osmium, one of the densest metals, is only about 8.4 cc; that of beryllium is only about 4.86 cc.