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  2. Prepupa - Wikipedia

    en.wikipedia.org/wiki/Prepupa

    The prepupa is a stage in the life cycle of certain insects, following the larva or nymph and preceding the pupa. It occurs in both holometabolous and hemimetabolous insects. Examples

  3. Systems chemistry - Wikipedia

    en.wikipedia.org/wiki/Systems_chemistry

    Systems chemistry is the science of studying networks of interacting molecules, to create new functions from a set (or library) of molecules with different hierarchical levels and emergent properties. [1] [2] Systems chemistry is also related to the origin of life (abiogenesis). [3]

  4. Equilibrium chemistry - Wikipedia

    en.wikipedia.org/wiki/Equilibrium_chemistry

    In this sense a system in chemical equilibrium is in a stable state. The system at chemical equilibrium will be at a constant temperature, pressure or volume and a composition. It will be insulated from exchange of heat with the surroundings, that is, it is a closed system. A change of temperature, pressure (or volume) constitutes an external ...

  5. Gibbs–Duhem equation - Wikipedia

    en.wikipedia.org/wiki/Gibbs–Duhem_equation

    For a simple system with different components, there will be + independent parameters or "degrees of freedom". For example, if we know a gas cylinder filled with pure nitrogen is at room temperature (298 K) and 25 MPa, we can determine the fluid density (258 kg/m 3 ), enthalpy (272 kJ/kg), entropy (5.07 kJ/kg⋅K) or any other intensive ...

  6. Reaction progress kinetic analysis - Wikipedia

    en.wikipedia.org/wiki/Reaction_progress_kinetic...

    Generally, this analysis involves a system in which the concentrations of multiple reactants are changing measurably over the course of the reaction. As the mechanism can vary depending on the relative and absolute concentrations of the species involved, this approach obtains results that are much more representative of reaction behavior under ...

  7. Chemical thermodynamics - Wikipedia

    en.wikipedia.org/wiki/Chemical_thermodynamics

    Starting from the first and second laws of thermodynamics, four equations called the "fundamental equations of Gibbs" can be derived. From these four, a multitude of equations, relating the thermodynamic properties of the thermodynamic system can be derived using relatively simple mathematics. This outlines the mathematical framework of ...

  8. Accelerated solvent extraction - Wikipedia

    en.wikipedia.org/wiki/Accelerated_solvent_extraction

    The extraction cell is filled with the solid sample to be examined and placed in a temperature-controllable oven. After adding the solvent, the cell is heated at constant pressure (adjustable between 0.3 and 20 MPa) up to a maximum temperature of 200°C and kept at constant conditions for a while so that equilibrium can be established.

  9. Aqueous two-phase system - Wikipedia

    en.wikipedia.org/wiki/Aqueous_two-phase_system

    It is a common observation that when oil and water are poured into the same container, they separate into two phases or layers, because they are immiscible.In general, aqueous (or water-based) solutions, being polar, are immiscible with non-polar organic solvents (cooking oil, chloroform, toluene, hexane etc.) and form a two-phase system.