enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Internal energy - Wikipedia

    en.wikipedia.org/wiki/Internal_energy

    The internal energy of a thermodynamic system is the energy of the system as a state function, measured as the quantity of energy necessary to bring the system from its standard internal state to its present internal state of interest, accounting for the gains and losses of energy due to changes in its internal state, including such quantities as magnetization.

  3. Isobaric process - Wikipedia

    en.wikipedia.org/wiki/Isobaric_process

    where W is work, U is internal energy, and Q is heat. [1] Pressure-volume work by the closed system is defined as: = where Δ means change over the whole process, whereas d denotes a differential. Since pressure is constant, this means that =.

  4. Departure function - Wikipedia

    en.wikipedia.org/wiki/Departure_function

    For example, to evaluate enthalpy change between two points h(v 1,T 1) and h(v 2,T 2) we first compute the enthalpy departure function between volume v 1 and infinite volume at T = T 1, then add to that the ideal gas enthalpy change due to the temperature change from T 1 to T 2, then subtract the departure function value between v 2 and ...

  5. Equation of state - Wikipedia

    en.wikipedia.org/wiki/Equation_of_state

    In physics and chemistry, an equation of state is a thermodynamic equation relating state variables, which describe the state of matter under a given set of physical conditions, such as pressure, volume, temperature, or internal energy. [1] [2] Most modern equations of state are formulated in the Helmholtz free energy.

  6. Isothermal process - Wikipedia

    en.wikipedia.org/wiki/Isothermal_process

    To maintain the constant temperature energy must leave the system as heat and enter the environment. If the gas is ideal, the amount of energy entering the environment is equal to the work done on the gas, because internal energy does not change. For isothermal expansion, the energy supplied to the system does work on the surroundings.

  7. Heat equation - Wikipedia

    en.wikipedia.org/wiki/Heat_equation

    Let = (,) be the internal energy (heat) per unit volume of the bar at each point and time. The rate of change in heat per unit volume in the material, ∂ Q / ∂ t {\displaystyle \partial Q/\partial t} , is proportional to the rate of change of its temperature, ∂ u / ∂ t {\displaystyle \partial u/\partial t} .

  8. Standard enthalpy of reaction - Wikipedia

    en.wikipedia.org/wiki/Standard_enthalpy_of_reaction

    Such thermal energy manifests itself, however, in changes in the non-chemical state variables (such as temperature, pressure, volume) of the joint systems, as well as the changes in the mole numbers of the chemical constituents that describe the chemical reaction. [citation needed] Internal energy is defined with respect to some standard state.

  9. Helmholtz free energy - Wikipedia

    en.wikipedia.org/wiki/Helmholtz_free_energy

    The Helmholtz free energy is defined as [3], where . F is the Helmholtz free energy (sometimes also called A, particularly in the field of chemistry) (SI: joules, CGS: ergs),; U is the internal energy of the system (SI: joules, CGS: ergs),