Question

5) The reaction PC13(g) + Cl2(g) → PC15(g) has a AS of -170.2 J/molK and a AHⓇ of -87.9 kJ/mol. Assuming the values of AHⓇ and AS are constant, what is the AGⓇ value for the reaction at 120°C? A) -108.3 kJ/mol B) -21.0 kJ/mol C) -154.8 kJ/mol D) -67.5 kJ/mol 6) Which of the following observations indicates that the enthalpy change of a reaction does NOT determine if a reaction is spontaneous? A) Organic compounds can burn in the presence of oxygen. B) Water condenses on a glass surface if the temperature is below 100°C. C) Ice melts spontaneously at temperatures above 0°C. D) Hydrogen and oxygen do not react at room temperature without a spark. 7) Which of the following substances has the least entropy? A) B(s) B) He(g) C) Fe(s) D) H2(1) 8) The standard free energy change for the reaction H2(g) + O2(g) → H2O2 (g) has the value of -105.5 kJ/mol at 25°C. What is the value of the equilibrium constant Kp for this reaction? A) 2.2 x 1022 B) 1.7 C) 75 D) 3.1 x 1018 9) The reaction 2NH3(g) → N2H4(g) + Hbg

Answer 1

∆S° and ∆H ° are given so ∆G° can be calculated as-

Given DS' = -17002 Jmolk DH = -8709 kJ/mol = -87900 J/mol. AGO AHO- Tasº at Taroc -87900J - Rocx (-170.2 | . molk mol = 87900 - more 393 K X (-17009) ] molk 5 -9 101104 pero AG -21.01 kJ/mol