why dry ice have no water?

Dry ice is a common name that actually refers to the solid form of frozen carbon dioxide which is a gas. If you drop the temperature down past minus 78.5 C, carbon dioxide will freeze from gaseous straight into solid phase. However, it reverses back from solid to gaseous state through sublimation without going through the liquid phase. No water ever exists in the process so you won't see any.

Dry ice is solid carbon dioxide, at room temperature and pressure of 6079.8 kPa pressure, the condensation of carbon dioxide into a colorless liquid, and then rapidly evaporated at low pressure, then condensed into an ice-like solid blocks of pressed material, the temperature was minus 78.5 ℃, which is the dry ice. Dry ice storage is 1.5 times more water ice to absorb heat after the sublimation of carbon dioxide gas, no residue, non-toxic, no smell, there are sterilization effect. After it is heated without liquefaction, and direct gasification.
After it is heated without liquefaction, and direct gasification. Dry ice is solid carbon dioxide, due to the temperature of dry ice is very low, the temperature is minus 78.5 degrees, so often used to keep objects in the maintenance of frozen or low temperature. At room temperature, pressurized carbon dioxide gas to about 101325Pa, when part of the steam is cooled to -56 ℃ or so, they will freeze into snow-like solid carbon dioxide. Thermal gasification solid carbon dioxide, large, at -60 ℃ when 364.5J / g, gasification at atmospheric pressure when the ambient temperature dropped to -78 ℃ can around, and will not produce liquid, so they are called"Dry ice".