value, calculate delta G. 3) Given a chemical equation, its deltas, and if it is endothermic or exothermic, say whether it is always, never, or conditionally spontaneous. 4) Given a

Consider the following reaction at 25C: Cl2(g)2Cl(g)K=1.01037 (a) Calculate G for the reaction at 25C. (b) Calculate G f for Cl(g) at 25C.

Thermite reactions have been used for welding metal parts such as railway rails and in metal refining. One such thermite reaction is Fe2O3(s)+2Al(s)Al2O3(s)+2Fe(s). Is the reaction spontaneous at room temperature under standard conditions? During the reaction, the surroundings absorb 851.8 kJ/mol of heat.

Many plastic materials are organic polymers that contain carbon and hydrogen. The oxidation of these plastics in air to farm carbon dioxide and water is a spontaneous process; however, plastic materials tend to persist in the environment. Explain.

The free energy change, G, for a process at constant temperature and pressure is related to Suniv and reflects the spontaneity of the process. How is G related to Suniv? When is a process spontaneous? Nonspontaneous? At equilibrium? G is a composite term composed of H, T, and S. What is the G equation? Give the four possible sign combinations for H and S. What temperatures are required for each sign combination to yield a spontaneous process? If G is positive, what does it say about the reverse process? How does the G = H TS equation reduce when at the melting-point temperature of a solid-to-liquid phase change or at the boiling-point temperature of a liquid-to-gas phase change? What is the sign of G for the solid-to-liquid phase change at temperatures above the freezing point? What is the sign of G for the liquid-to-gas phase change at temperatures below the boiling point?

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)

What is entropy? Why is entropy important?

Sodium carbonate, also called washing soda, can be made by heating sodium hydrogen carbonate: 2NaHCO3(l)Na2CO3(s)+CO2(g)+H2O(l) H=+135.6kJ;G=+34.6kJ at 25C (a) Calculate S for this reaction. Is the sign reasonable? (b) Calculate G at 0 K; at 1000 K.

Given that H f for HF(aq) is -320.1 kJ/mol and S for HF(aq) is 88.7 J/mol K, find Ka for HF at 25C.

10.51 The combustion of acetylene was used in welder's torches for many years because it produces a very hot flame: C2H2(g)+52O2(g)2CO2(g)+H2O(g) H= -1255.5 kJ (a) Use data in Appendix E to calculate S for this reaction, (b) Calculate G and show that the reaction is spontaneous at 25°C. (c) Ls there any temperature range in which this reaction is not spontaneous? (d) Do you think you could use Equation 10.4 to calculate such a temperature range reliably? Explain your answer.