3.5 Calculate the change in entropy when 100 g of water at 80 °C is poured into 100 g of water at 10 °C in an insulated vessel given that Cp,m = 75.5 J K-1 mol-1.

It has been demonstrated that buckminsterfullerene (C60), another allotrope of carbon (Section 2.3), may be converted into diamond at room temperature and 20,000 atmospheres pressure (about 2 GPa). The standard enthalpy of formation, fH, for buckminsterfullerene is 2320 kJ/mol at 298.2 K. a. Calculate rH for the conversion of C60 to diamond at standard state conditions and 2982 K. b. Assuming that the standard entropy per mole of carbon in both C60 and diamond is comparable (both about 23 J/K mol), is the conversion of C60 to diamond product-favoredat room temperature?

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)

What is the sign of the standard Gibbs free-energy change at low temperatures and at high temperatures for the synthesis of ammonia? 3H2(g) + N2(g) 2NH3(g)

Appendix J lists standard molar entropies S, not standard entropies of formation rS. Why is this possible forentropy but not for internal energy, enthalpy, or Gibbsfree energy?

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.

When 1.000 g of ethylene glycol, C2H6O2, is burned at 25C and 1.00 atmosphere pressure, H2O(l) and CO2(g) are formed with the evolution of 19.18 kJ of heat. a Calculate the molar enthalpy of formation of ethylene glycol. (It will be necessary to use data from Appendix C.) b Gf of ethylene glycol is 322.5 kJ/mol. What is G for the combustion of 1 mol ethylene glycol? c What is S for the combustion of 1 mol ethylene glycol?

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)

Without looking up their standard entropies in reference tables, identify which of the following lists the materials in order of increasing entropy. (a) H2O() NaCl(s) NH3(g) (b) H2O() NH3(g) NaCl(s) (c) NaCl(s) H2O() NH3(g) (d) NH3(g) H2O() NaCl(s)

2. Which of the following is true for a spontaneous process but not for a nonspontaneous process? Energy in the universe is concentrated conserved dispersed not conserved