Search results
Results from the WOW.Com Content Network
Dichloromethane (DCM, methylene chloride, or methylene bichloride) is an organochlorine compound with the formula C H 2 Cl 2. This colorless, volatile liquid with a chloroform-like, sweet odor is widely used as a solvent. Although it is not miscible with water, it is slightly polar, and miscible with many organic solvents. [12]
Liquid carbon dioxide is the liquid state of carbon dioxide (CO 2 ), which cannot occur under atmospheric pressure. It can only exist at a pressure above 5.1 atm (5.2 bar; 75 psi), under 31.1 °C (88.0 °F) (temperature of critical point ) and above −56.6 °C (−69.9 °F) (temperature of triple point ). [ 1 ]
The most important is dichloromethane, which is mainly used as a solvent. Chloromethane is a precursor to chlorosilanes and silicones . Historically significant (as an anaesthetic), but smaller in scale is chloroform, mainly a precursor to chlorodifluoromethane (CHClF 2 ) and tetrafluoroethene which is used in the manufacture of Teflon.
Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well. Liquefaction is used for analyzing the fundamental properties of gas molecules (intermolecular forces), or for the storage of gases, for example: LPG , and in refrigeration and air conditioning .
Dry ice (solid carbon dioxide) effects are produced by heating water to or near boiling in a suitable container (for example: a 55-gallon drum with water heater coils in it), and then dropping in one or more pieces of dry ice. Because carbon dioxide cannot exist as a liquid at atmospheric pressure, the dry ice sublimates and instantly produces ...
For frequent and industrial use, cleaning and degreasing may be replaced by supercritical carbon dioxide or dry Ice blasting, which is abrasive. This requires a setup to apply the carbon dioxide. While the harmful vapors are eliminated, the CO 2 must be ventilated. Applying the carbon dioxide causes electrostatic discharge by the expanding gas.
Dry distillation is the heating of solid materials to produce gaseous products (which may condense into liquids or solids). The method may involve pyrolysis or thermolysis, or it may not (for instance, a simple mixture of ice and glass could be separated without breaking any chemical bonds, but organic matter contains a greater diversity of molecules, some of which are likely to break).
Liquid properties Std enthalpy change of formation, Δ f H o liquid: −124.3 kJ/mol Standard molar entropy, S o liquid: 174.5 J/(mol K) Heat capacity, c p: 102.3 J/(mol K) Gas properties Std enthalpy change of formation, Δ f H o gas: −95.52 kJ/mol Standard molar entropy, S o gas: 270.28 J/(mol K) Heat capacity, c p? J/(mol K) van der Waals ...