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Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the liquid state. [ 1 ] The verb form of sublimation is sublime, or less preferably, sublimate. [ 2 ]Sublimate also refers to the product obtained by sublimation. [ 2 ][ 3 ] The point at which sublimation occurs rapidly (for further ...
Freeze-dried strawberries. Freeze drying, also known as lyophilization or cryodesiccation, is a low temperature dehydration process [1] that involves freezing the product and lowering pressure, thereby removing the ice by sublimation. [2] This is in contrast to dehydration by most conventional methods that evaporate water using heat.
Enthalpy of sublimation. In thermodynamics, the enthalpy of sublimation, or heat of sublimation, is the heat required to sublimate (change from solid to gas) one mole of a substance at a given combination of temperature and pressure, usually standard temperature and pressure (STP). It is equal to the cohesive energy of the solid.
The low temperature and direct sublimation to a gas makes dry ice an effective coolant, since it is colder than water ice and leaves no residue as it changes state. [4] Its enthalpy of sublimation is 571 kJ/kg (25.2 kJ/mol, 136.5 calorie/g). Dry ice is non-polar, with a dipole moment of zero, so attractive intermolecular van der Waals forces ...
Lower temperatures in a boiler firebox might evaporate water more quickly as a result; compare Mpemba effect. An alternative approach was to increase the temperature beyond the Leidenfrost point. Fairbairn considered this, too, and may have been contemplating the flash steam boiler, but considered the technical aspects insurmountable for the time.
In thermodynamics, the triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium. [1] It is that temperature and pressure at which the sublimation, fusion, and vaporisation curves meet. For example, the triple point of mercury occurs at a ...
The dehydration of freezer-burned food is caused by water sublimating from the food into the surrounding atmosphere. The lost water may then be deposited elsewhere in the food and packaging as snow-like crystals. [3] [4] Fluctuation of temperatures in a freezer above 0 °F (−17.8 °C), can also speed up freezer burn. [5]
With cold food, it should be discarded after sitting at room temperature for over two hours, and one hour if it’s been sitting at a temperature above 90F. Show comments Advertisement