Search results
Results from the WOW.Com Content Network
Nitrogen is a liquid under −195.8 °C (77.3 K).. In physics, cryogenics is the production and behaviour of materials at very low temperatures.. The 13th International Institute of Refrigeration's (IIR) International Congress of Refrigeration (held in Washington, DC in 1971) endorsed a universal definition of "cryogenics" and "cryogenic" by accepting a threshold of 120 K (−153 °C) to ...
Because of the extremely low temperatures, diagnosing the chemical status is a major issue when studying low temperature physics and chemistry. [ clarification needed ] The primary techniques in use today are optical - many types of spectroscopy are available, but these require special apparatus with vacuum windows that provide room temperature ...
The following is a timeline of low-temperature technology and cryogenic technology (refrigeration down to close to absolute zero, i.e. –273.15 °C, −459.67 °F or 0 K). [1] It also lists important milestones in thermometry , thermodynamics , statistical physics and calorimetry , that were crucial in development of low temperature systems.
When both temperature and pressure are held constant, and the number of particles is expressed in moles, the chemical potential is the partial molar Gibbs free energy. [ 1 ] [ 2 ] At chemical equilibrium or in phase equilibrium , the total sum of the product of chemical potentials and stoichiometric coefficients is zero, as the free energy is ...
Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation.
Unlike a classical ideal gas, whose pressure is proportional to its temperature =, where P is pressure, k B is the Boltzmann constant, N is the number of particles (typically atoms or molecules), T is temperature, and V is the volume, the pressure exerted by degenerate matter depends only weakly on its temperature.
Low-temperature helium is the only known exception to the general rule. [7] Helium-3 has a negative enthalpy of fusion at temperatures below 0.3 K. Helium-4 also has a very slightly negative enthalpy of fusion below 0.8 K. This means that, at appropriate constant pressures, heat must be added to these substances in order to freeze them. [8]
The conflict is resolved as follows: At a certain temperature the quantum nature of matter starts to dominate the behavior. Fermi particles follow Fermi–Dirac statistics and Bose particles follow Bose–Einstein statistics. In both cases the heat capacity at low temperatures is no longer temperature independent, even for ideal gases. For ...