The vaporisation of a certain element at 23.0 oC has the following enthalpy and entropy values: Hvap = 7.00 kJ mol-1 and Svap = 246 J K mol-1. What is the total entropy change (Stot) for the vaporisation of this element, in J K-1 mol-1? (Enter your answer as a number only, with the correct number of significant figures!)

Consider the reaction: 2 NO2 (g) = N204 (g) The standard-state enthalpies of formation (AHf) for NO2(g) and N204(g) are +33.2 and +9.2 kJ mol-1, respectively. The third law entropies (S°) for NO210) and N,04lg) are 240.1 and 98.0 J K-1 mol-1, respectively. a) What is the value of AG° for this reaction? b) What is the equilibrium constant (K) for the reaction at 25 °C? c) What is the value of K for the same reaction at -25 °C? d) What is AG for the reaction at 25 °C when both gases initially exist at 2.2 atm pressure?

The heat of fusion AH, of methanol (CH,OH) is 3.16 kJ/mol. Calculate the change in entropy AS when 23. g of methanol melts at -98.0 °C. Be sure your answer contains a unit symbol. Round your answer to 2 significant digits. 0 0 X H 010

6. A 3.131 g sample of acetonitrile (C2H3N) is placed in a bomb calorimeter that has a previously measured heat capacity of 8.21 kJ.°C-1. After the sample is combusted, a temperature increase of 11.7°C is measured. What is the molar enthalpy of comubstion of acetonitrile, in kJ-mol-1?