Search results
Results From The WOW.Com Content Network
A cooling bath or ice bath, in laboratory chemistry practice, is a liquid mixture which is used to maintain low temperatures, typically between 13 °C and −196 °C. These low temperatures are used to collect liquids after distillation , to remove solvents using a rotary evaporator , or to perform a chemical reaction below room temperature ...
Dry ice: Ethylene glycol-15 Ice: Sodium chloride-20 1 to 3 ratio of salt to ice. Dry ice: Tetrachloroethylene-22 Dry ice: Carbon Tetrachloride-23 Dry ice: 1,3-Dichlorobenzene-25 Dry ice: o-Xylene-29 Liquid N 2: Bromobenzene-30 Dry ice: m-Toluidine-32 Dry ice: 3-Heptanone-38 Ice: Calcium chloride hexahydrate -40 1 to 0.8 ratio of salt to ice ...
One example of deposition is the process by which, in sub-freezing air, water vapour changes directly to ice without first becoming a liquid. This is how frost and hoar frost form on the ground or other surfaces. Another example is when frost forms on a leaf. For deposition to occur, thermal energy must be removed from a gas.
The Wegener–Bergeron–Findeisen process (after Alfred Wegener, Tor Bergeron, and Walter Findeisen []), (or "cold-rain process") is a process of ice crystal growth that occurs in mixed phase clouds (containing a mixture of supercooled water and ice) in regions where the ambient vapor pressure falls between the saturation vapor pressure over water and the lower saturation vapor pressure over ice.
In practice, a mechanical freezing process is usually used instead due to cost. There has been continuous optimization of the freezing rate in mechanical freezing to minimize ice crystal size. [2] Flash freezing techniques are also used to freeze biological samples quickly so that large ice crystals cannot form and damage the sample. [5]
In chemistry, a condenser is laboratory apparatus used to condense vapors – that is, turn them into liquids – by cooling them down. [1] Condensers are routinely used in laboratory operations such as distillation, reflux, and extraction. In distillation, a mixture is heated until the more volatile components boil off, the vapors are ...
In chemistry a cooling bath may be used to control the temperature of a strongly exothermic reaction. A frigorific mixture may be used as an alternative to mechanical refrigeration. For example to fit two machined metal parts together, one part is placed in a frigorific mixture, causing it to contract so that may be easily inserted into the ...
In the laboratory, lauric acid may be used to investigate the molar mass of an unknown substance via the freezing-point depression. The choice of lauric acid is convenient because the melting point of the pure compound is relatively high (43.8 °C). Its cryoscopic constant is 3.9 °C·kg/mol. By melting lauric acid with the unknown substance ...