Crystallization separates a solid dissolved in a liquid that has formed a solution. To crystallize the solid, the solution is heated in an open container to allow the liquid to evaporate, leaving the crystalline solid behind.Continue Reading
Crystallization can be naturally or artificially induced. In addition to crystals that precipitate from a liquid solution, crystallization can also occur in a molten liquid that is cooled or a gas that is deposited on a surface. Crystallization occurs in two major steps: nucleation and crystal growth.
During the nucleation phase, the solvent molecules dispersed in the solution are attracted to one another, forming nanometer-sized clusters. Halting the process at this stage and stabilizing the nanoclusters is a commonly used technique in the synthesis of nanoparticles. Leaving the process to continue yields stable nuclei that persist without dissolving back into the solution. The critical size that these nuclei need to reach to become stable depends on system conditions such as the solution temperature and solvent concentration.
The crystal growth stage involves the subsequent attraction of additional solvent molecules to the nuclei that have previously succeeded in achieving critical size. This process continues so long as the solution is supersaturated: having more solvent dissolved than it can sustain at these particular conditions.Learn more about Chemistry
The process by which a solid becomes a liquid is called melting. Melting is one of the six phase transitions by which matter undergoes a change in state.Full Answer >
The red liquid inside of a thermometer is alcohol. When the temperature changes, the alcohol expands, providing a reading based on the thermometer's scale. Red dye is used to color the clear alcohol so that someone is able to easily read the thermometer.Full Answer >
A hydrometer measures the specific gravity, or relative density, of a liquid. Resembling a thermometer with a weighted bulb at one end, a hydrometer is gently lowered into the liquid to be tested, which is usually contained in a graduated cylinder, and allowed to float freely. When it comes to rest, the point at which the surface of the liquid aligns with the calibrations on the instrument's side is noted.Full Answer >
Flash point tables generally contain information that identifies the liquid or liquids in question along with the flash points, fire points and auto ignition temperatures of the liquids shown. Flash point tables may also contain information or notes regarding the testing methods used to determine the temperatures stated in the table, the conditions under which testing was performed and anything else relevant to the testing or safe handling of the liquid in question.Full Answer >