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Supercritical ethane, fluid. [1] In thermodynamics, a critical point (or critical state) is the end point of a phase equilibrium curve. One example is the liquid–vapor critical point, the end point of the pressure–temperature curve that designates conditions under which a liquid and its vapor can coexist. At higher temperatures, the gas ...
Oxygen is a chemical element; it has symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is the most abundant element in Earth's crust, and after hydrogen and helium, it ...
Phase diagram for solid oxygen. Six different phases of solid oxygen are known to exist: [1] [6] α-phase: light blue – forms at 1 atm, below 23.8 K, monoclinic crystal structure, space group C2/m (no. 12). β-phase: faint blue to pink – forms at 1 atm, below 43.8 K, rhombohedral crystal structure, space group R 3 m (no. 166). At room ...
A typical phase diagram.The solid green line applies to most substances; the dashed green line gives the anomalous behavior of water. 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]
Ellingham diagrams are a particular graphical form of the principle that the thermodynamic feasibility of a reaction depends on the sign of Δ G, the Gibbs free energy change, which is equal to Δ H − T Δ S, where Δ H is the enthalpy change and Δ S is the entropy change. The Ellingham diagram plots the Gibbs free energy change (Δ G) for ...
Singlet oxygen, systematically named dioxygen (singlet) and dioxidene, is a gaseous inorganic chemical with the formula O=O (also written as 1[O2] or 1O2), which is in a quantum state where all electrons are spin paired. It is kinetically unstable at ambient temperature, but the rate of decay is slow. The lowest excited state of the diatomic ...
A phase diagram in physical chemistry, engineering, mineralogy, and materials science is a type of chart used to show conditions (pressure, temperature, etc.) at which thermodynamically distinct phases (such as solid, liquid or gaseous states) occur and coexist at equilibrium.
An enthalpy–entropy chart, also known as the H–S chart or Mollier diagram, plots the total heat against entropy, [1] describing the enthalpy of a thermodynamic system. [2] A typical chart covers a pressure range of 0.01–1000 bar, and temperatures up to 800 degrees Celsius. [3] It shows enthalpy in terms of internal energy , pressure and ...