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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 ...
Cryochemistry is the study of chemical interactions at temperatures below −150 °C (−238 °F; 123 K). [1] It is derived from the Greek word cryos, meaning 'cold'.It overlaps with many other sciences, including chemistry, cryobiology, condensed matter physics, and even astrochemistry.
A definition of temperature can be based on the relationship: = The relationship suggests that a positive temperature corresponds to the condition where entropy, S, increases as thermal energy, q rev, is added to the system. This is the "normal" condition in the macroscopic world, and is always the case for the translational, vibrational ...
The third law of thermodynamics states: As the temperature of a system approaches absolute zero, all processes cease and the entropy of the system approaches a minimum value. This law of thermodynamics is a statistical law of nature regarding entropy and the impossibility of reaching absolute zero of temperature. This law provides an absolute ...
The definition of the Gibbs function is = + where H is the enthalpy defined by: = +. Taking differentials of each definition to find dH and dG, then using the fundamental thermodynamic relation (always true for reversible or irreversible processes): = where S is the entropy, V is volume, (minus sign due to reversibility, in which dU = 0: work other than pressure-volume may be done and is equal ...
An example of a system that does not have a unique ground state is one whose net spin is a half-integer, for which time-reversal symmetry gives two degenerate ground states. For such systems, the entropy at zero temperature is at least k B ln(2) (which is negligible on a macroscopic scale).
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.
Heat of higher temperature is richer, is capable of doing more work. Work may be regarded as heat of an infinitely high temperature, as unconditionally available heat." [12] This is why temperature is the particular variable indicated by the zeroth law's statement of equivalence.