Predict which substance has greater molar entropy. Explain.(a) CH3OH(l) or C2H5OH(l)             (b) KClO3(s) or KClO3(aq)(c) Na(s) or K(s)

Describe how the standard entropy of hydrogen gas at 25C can be obtained from heat measurements.

What is the sign of the standard Gibbs free-energy change at low temperatures and at high temperatures for the combustion of acetaldehyde? CH3CHO(l)+52O2(g)2CO2+2H2O(l)

Determine the entropy change for the combustion of gaseous propane, C3H8, under the standard conditions to give gaseous carbon dioxide and water.

Consider the reaction of 1 mol H2(g) at 25C and 1 atm with 1 mol Br2(l) at the same temperature and pressure to produce gaseous HBr at these conditions. If this reaction is run in a controlled way to generate work, what is the maximum useful work that can be obtained? How much entropy is produced in this case?

What is the sign of the standard Gibbs free-energy change at low temperatures and at high temperatures for the formation of hydrogen sulfide from the elements? H2(g)+18S8(s)H2S(g)

Chemists and engineers who design nuclear power plants have to worry about high-temperature reactions because it is possible for water to decompose. (a) Under what conditions does this reaction occur spontaneously? 2H2O(g) 2H2(g) + O2(g) (b) Under conditions where the decomposition of water is spontaneous, do nuclear engineers have to worry about an oxygen/hydrogen explosion? Justify your answer.

Explain why absolute entropies can be measured.

On the basis of your experience, predict which of the following reactions are spontaneous. (a) CO2(s)CO2(g) at 25°C (b) NaCl(s)NaCl(l) at 25°C (c) 2NaCl(s)2Na(s)+Cl2(g) (d) CO2(g)C(s)+O2(g)

The standard molar entropy of methanol vapor, CH3OH(g), is 239.8 J K1 mol-1. (a) Calculate the entropy change for the vaporization of 1 mol methanol (use data from Table 16.1 or Appendix J). (b) Calculate the enthalpy of vaporization of methanol, assuming that rS doesnt depend on temperature and taking the boiling point of methanol to be 64.6C.