Vaporization change of entropy

Solve Eq. (6.72) for the latent heat and divide by T to get the entropy change of vaporization ... 

The enthalpy change and entropy change of vaporization are directly related ... 

The phase envelope in Fig. 1 below 8 atm, (36.33°K) was constructed using YendalPs saturated vapor curve and the calculated entropy change of vaporization. The upper portion of the phase envelope was constinicted by a trial-and-error method since these points as given by Yendall seemed to be in doubt. 

For each of the substances in Table A.7, calculate the entropy change of vaporization at the normal boiling temperature and compare your result with Trouton s rule. Which of the substances qualify as normal liquids ... 

Self-Test 7.14A Calculate the entropy change of the surroundings when 1.00 mol H20(l) vaporizes at 90°C and I bar. Take the enthalpy of vaporization of water as 40.7 kj-mol. ... 

The standard entropy of vaporization of benzene is approximately 85 J-K -mol-1 at its boiling point, (a) Estimate the standard enthalpy of vaporization of benzene at its normal boiling point of 80.°C. (b) What is the standard entropy change of the surroundings when 10. g of benzene, CfiHfi, vaporizes at its normal boiling point ... 

At its boiling point, what is the entropy change of benzene from a liquid to vapor per gram Use Table 6.1. 

J1 The state of l(lbm) of steam is changed from saturated vapor at 10(psia) to superheated vapor at 30(psia) and 1,200(°F). What are the enthalpy and entropy changes of the steam What would the enthalpy and entropy changes be if steam were an ideal gas ... 

A rigid vessel contains l(lbm) of saturated-vapor steam at 250(°F). Heat is extracted from the vessel until the pressure reaches 15(psia). What is the entropy change of the steam ... 

Table 3.1 displays the entropy changes of melting and vaporization for some pure substances. The entropy of vaporization is proportional to the ratio of the degree of randomness in the vapor and liquid phases. For a pure component, A.S. consists of translational, rotational, and conformational motion of molecules. The translational effect is the largest contribution to the entropy of vaporization. 

Estimate the entropy change of vaporizationof benzene at 323.15 K (50°C). The vapor pressure of benzene is given by the equation ... 

For the reverse change (condensation), A5 niv also equals zero, but AS°ys and ASsun have signs opposite those for vaporization. A similar treatment of a chemical change shows the same result the entropy change of the forward reaction is equal in magnitude but opposite in sign to the entropy change of the reverse reaction. Thus, when a system reaches equilibrium, neither the forward nor the reverse reaction is spontaneous, and so there is no net reaction in either direction. 

Diethyl ether is a hquid at normal temperature and pressure, and it bods at 3 5°C. Given that AH is 26.0 y/mol for the vaporization of diethyl ether, find its molar entropy change for vaporization. 

A For each process, tell whether the entropy change of the system is positive or negative, (a) Water vapor (the system) condenses as droplets on a cold windowpane. 

The enthalpy of vaporization of methanol is 35.27 kJ mol" at its normal boihng point of 64.1°C. Calculate (a) the entropy of vaporization of methanol at this temperature and (b) the entropy change of the surroundings. 

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