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    Home > Chemicals Industry > Chemical Technology > Calculation of entropy change

    Calculation of entropy change

    • Last Update: 2021-06-18
    • Source: Internet
    • Author: User
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    1.
    Calculate from the thermal effect Q r of the constant temperature reversible process

    For a constant temperature reversible process, the entropy change is equal to the quotient of the heating effect Q r and the temperature T, namely

    2.


    Obtained from the standard disease SmΘ

    If the response is

    aA+6B=cC+dD

    Then the reaction entropy becomes

    which is

    [Example 2-8] Find the △ r S m Θ of the reaction 2H 2 (g)+O 2 (g)=2H 2 O(g) at 298K .


    A known

    3.


    Obtained from other thermodynamic data

    According to the Gibbs-Holmholtz formula (introduced later in this chapter)


    From the free energy change △ r G m Θ and the enthalpy change △ r H m Θ data of the reaction, the entropy change △ r S m Θ can be obtained


     

     

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