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Reactions, chemical free energy changes

The relationship between Q and signals the direction of a chemical reaction. The free energy change, A G, also signals the direction of a chemical reaction. These two criteria can be compared ... [Pg.1150]

An important result of nonequilibrium thermodynamics (Boudard, 1976) is that the ratio of the forward and reverse rates of a chemical reaction varies with the reaction s free energy change according to... [Pg.247]

The Gibbs free energy G is a central thermodynamic quantity in understanding chemistry. The Gibbs free energy determines whether a reaction, or perhaps its reverse reaction, will proceed spontaneously. It provides for the location of chemical equilibrium, at which there is no net forward or reverse reaction. The free-energy change of a reaction determines the equilibrium constant, which also determines the reverse rate constant for a reaction, if the forward rate constant is known. [Pg.372]

The free-energy change for a reaction is independent of the pathway by which the reaction occurs. Free-energy changes are additive the net chemical reaction that results from successive reactions sharing a common intermediate has an overall free-energy change that is the sum of the AG values for the individual reactions. [Pg.495]

Fuel cell electrochemical reactions convert free energy change associated with the chemical reaction into electrical energy directly. The Gibbs free energy change in a chemical reaction is a measure of the maximmn net work obtainable from a chemical reaction [24]. [Pg.288]

What is the useful work obtained in the ideal situation in which a chemical reaction with free-energy change AG is mn so that it produces no entropy ... [Pg.794]

The newly defined quantity AG is the so-called total free energy change of the system due to the undergoing chemical reactions. A free energy change can be defined for each reaction ... [Pg.11]

Gibbs-Helmholtz equation This equation relates the heats and free energy changes which occur during a chemical reaction. For a reaction carried out at constant pressure... [Pg.190]

Having calculated the standai d values AyW and S" foi the participants in a chemical reaction, the obvious next step is to calculate the standard Gibbs free energy change of reaction A G and the equilibrium constant from... [Pg.163]

Cell Volta.ge a.ndIts Components. The minimum voltage required for electrolysis to begin for a given set of cell conditions, such as an operational temperature of 95°C, is the sum of the cathodic and anodic reversible potentials and is known as the thermodynamic decomposition voltage, is related to the standard free energy change, AG°C, for the overall chemical reaction,... [Pg.484]

Estimation of the free-energy change associated with a reaction permits the calcula-aon of the equilibrium position for a reaction and indicates the feasibility of a given chemical process. A positive AG° imposes a limit on the extent to which a reaction can x cur. For example, as can be calculated using Eq. (4.2), a AG° of 1.0 kcal/mol limits conversion to product at equilibrium to 15%. An appreciably negative AG° indicates that e reaction is thermodynamically favorable. [Pg.189]

Equation (9.5) enables us to calculate ArG for a chemical reaction under a given set of activity conditions when we know the free energy change for the reaction under the standard state condition. Of special interest are the activities when reactants and products are at equilibrium. Under those conditions,... [Pg.436]

In the introductory chapter we stated that the formation of chemical compounds with the metal ion in a variety of formal oxidation states is a characteristic of transition metals. We also saw in Chapter 8 how we may quantify the thermodynamic stability of a coordination compound in terms of the stability constant K. It is convenient to be able to assess the relative ease by which a metal is transformed from one oxidation state to another, and you will recall that the standard electrode potential, E , is a convenient measure of this. Remember that the standard free energy change for a reaction, AG , is related both to the equilibrium constant (Eq. 9.1)... [Pg.176]

Recall from Chapter j 4 that the free energy change for a chemical process, A G, Is a signpost for spontaneity. Equation relates A G to concentrations through the reaction quotient Q ... [Pg.1149]

Fig. 10. Relationship between (AC i,2 —0.5 ACJi.i) and the standard free energy change (AG ij) of the redox reactions at 25 °C. Open circles, Ce(IV) + Fe(phen)3 reactions in 0.50 Af HjS04. Closed circles, Fe + +Fe(phen)3 reactions in 0.50 M HCIO4. Numbers refer to complexes in Table 32. (From Dulz and Satin, by courtesy of The American Chemical Society.)... Fig. 10. Relationship between (AC i,2 —0.5 ACJi.i) and the standard free energy change (AG ij) of the redox reactions at 25 °C. Open circles, Ce(IV) + Fe(phen)3 reactions in 0.50 Af HjS04. Closed circles, Fe + +Fe(phen)3 reactions in 0.50 M HCIO4. Numbers refer to complexes in Table 32. (From Dulz and Satin, by courtesy of The American Chemical Society.)...
The free energy change in a chemical reaction is expressed in the same way as the enthalpy of the reaction is expressed. For example, the free energy change in the reaction... [Pg.241]


See other pages where Reactions, chemical free energy changes is mentioned: [Pg.18]    [Pg.495]    [Pg.40]    [Pg.572]    [Pg.178]    [Pg.11]    [Pg.1713]    [Pg.2174]    [Pg.118]    [Pg.20]    [Pg.181]    [Pg.489]    [Pg.425]    [Pg.312]    [Pg.434]    [Pg.352]    [Pg.358]    [Pg.359]    [Pg.369]    [Pg.1116]    [Pg.153]    [Pg.166]    [Pg.435]    [Pg.436]    [Pg.600]    [Pg.964]    [Pg.60]    [Pg.1027]    [Pg.55]    [Pg.140]    [Pg.75]    [Pg.191]    [Pg.242]    [Pg.262]    [Pg.379]   
See also in sourсe #XX -- [ Pg.440 , Pg.441 , Pg.442 , Pg.443 , Pg.445 , Pg.446 , Pg.447 , Pg.448 , Pg.449 , Pg.450 ]




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