Methane molar entropies

C14-0050. Table lists molar enthalpies of fusion of several substances. Calculate the molar entropy of fusion at its normal melting point for each of the following (a) argon (b) methane (c) ethanol and (d) mercury. 

Which would you expect to have a higher molar entropy at T =0, single crystals of CH4 or CH3D (methane in which one hydrogen atom has been replaced by deuterium) Why ... 

Make a rough, qualitative plot of the standard molar entropy versus temperature for methane from 0 K to 298 K. Incorporate the following data into your plot mp = —182°C bp = —164°C S° = 186.2 J/(K mol) at... 

Equations (2.28) and (2.29) indicate that the molar number of the products caused by the oxidation of hydrogen H2 and carbon monoxide CO are smaller than the total molar number of the reactants. Concerning the oxidation of CH4, the molar number of the products and reactants are equal. Thus, there is theoretically no change in the entropy for the last case. This is the reason for the low dependency of the Gibbs free enthalpy of the methane oxidation from the temperature. 

The expansion has been assumed to be adiabatic, and thus the entropy generated equals the entropy increase of the gas, AS, as the entropy change of the environment, AS0, can be set to zero because the process is adiabatic. The amount of lost work can now be calculated from the entropy values Sj and S2 of 1 mol of methane at the initial and final conditions, respectively. However, this requires knowledge not only of the final pressure P2, which is known, but also of the final temperature T2, which is unknown. Here, the first law helps us out. Applying Equation 2.39 and substituting zero for Win and Qout, we find AH = 0 or H2 = Hv From the IUPAC data series number 16, dealing with methane [1], we find that the molar enthalpy and entropy at initial conditions are, respectively,... 

Problem 9.5 In the process below, all streams are mixtures of methane/carbon monoxide with molar compositions indicated on the flow chart in Figure q-2. Calculate the material and energy balances and perform an entropy analysis of the mixing point, the heat exchanger, and of the entire process. The heat capacities of methane and carbon monoxide are Cpa = 40.8 J/mol K, and Cpb = 29.4 J/mol K, respectively. 

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