Total entropy change

This expression gives the average entropy change per chain to get the average for the sample, we multiply by the number v of subchains in the sample. The total entropy change is... 

Because the engine operates in cycles, it experiences no change in its own properties therefore the total entropy change of the engine and its associated heat reservoirs is given by equation 8 ... 

Notice that the second law refers to the total entropy change, involving both system and surroundings. For many spontaneous processes, the entropy change for the system is a negative quantity. Consider, for example, the rusting of iron, a spontaneous process ... 

Figure 2.13 Mixing of ideal gas A with ideal gas B at constant temperature and constant total pressure. The entropy change AS is given by equation (2.78).

The system ot interest and its surroundings constitute the isolated system to which the second law refers (Fig. 7.15). Only if the total entropy change,... 

Total entropy Fntropy change Entropy change... 

By considering the total entropy change, we can draw some far-reaching conclusions about processes going on in the universe. For instance, we saw in Section 6.3 that maximum work is achieved if expansion takes place reversibly, by matching the... 

EXAMPLE 7.12 Calculating the total entropy change for the expansion of an ideal gas... 

This equation shows how to calculate the total entropy change from information about the system alone. The limitation is that the equation is valid only at constant temperature and pressure. 

What is the total entropy change when 2.00 mol of water (A =6.01 kJ/mol) freezes at 0.0 °C in a freezer compartment whose temperature is held at -15 °C ... 

The problem asks for the total entropy change, which includes A S for the water and A S for the freezer compartment. When water freezes, heat flows from the water to its surroundings, the freezer compartment (see Eigure 14-61. Thus, q is negative for the water, whose entropy decreases. At the same time, q is positive for the freezer compartment, whose entropy increases. 

Equation gives the total entropy change A — A jS ystem + A Fjmygmjgjggs We can define the HFC as the system and the contents of the refrigerator as the immediate surroundings ... 

C14-0005. Calculate the total entropy change when 175 g of water at 0 °C freezes, transferring heat that causes HFC-134a to boil at -27 °C. 

Entropy changes are important in every process, but chemists are particularly interested in the effects of entropy on chemical reactions. If a reaction occurs under standard conditions, its entropy change can be calculated from absolute entropies using the same reasoning used to calculate reaction enthalpies from standard enthalpies of formation. The products of the reaction have molar entropies, and so do the reactants. The total entropy of the products is the sum of the molar entropies of the products multiplied by their stoichiometric coefficients in the balanced chemical equation. The total entropy of the reactants is a similar sum for the reactants. Equation... 

In words, in any process that occurs at constant T and P, the free energy change for the system is negative whenever the total entropy change is positive that is, whenever the overall process is spontaneous. Defining a new function and imposing some restrictions provides a way to use properties of a system to determine whether a process is... 

If the configurational entropy A>Sm is assumed to represent the total entropy change LSm on mixing, the free energy of mixing is simply obtained by combining Eqs. (10) and (20). That is,... 

As a first approximation, assume that the total entropy change, ASy, is made up solely of configurational entropy. This can be determined by using the Boltzmann equation for the entropy of a disordered system ... 

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