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That pressure causes the nitrocellulose molecules to bind back to each other or crystallize, and this results in the camphor molecules being shoved out of the material. Once exposed to the environment, camphor can undergo sublimation at room temperature, and the plastic reverts to brittle nitrocellulose.
Naphthalene is a solid that sublimes gradually at standard temperature and pressure, [9] at a high rate, with the critical sublimation point at around 80 °C (176 °F). [10] At low temperature, its vapour pressure is high enough, 1 mmHg at 53 °C, [11] to make the solid form of naphthalene evaporate into gas. On cool surfaces, the naphthalene ...
The form of the cooled surface often is a so-called cold finger which for very low-temperature sublimation may actually be cryogenically cooled. If the operation is a batch process , then the sublimed material can be collected from the cooled surface once heating ceases and the vacuum is released.
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 density of dry ice increases with decreasing temperature and ranges between about 1.55 and 1.7 g/cm 3 (97 and 106 lb/cu ft) below 195 K (−78 °C; −109 °F). [3] 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]
Much of the time, a recipe will provide certain cues and reminders of the places where these details of ingredient chemistry really matter, like when a recipe calls for a select number of "large ...
It was known that when the air temperature rises above freezing—air then becoming the obvious heat source—snow melts very slowly and the temperature of the melted snow is close to its freezing point. [5] In 1757, Black started to investigate if heat, therefore, was required for the melting of a solid, independent of any rise in temperature.
It’s the key to soft, chewy, and flavorful cookies.