c. 273 °C 8. For a given reaction, AH = +7.50 kJ/mol and AS = +70.74 J/(K mol). Above what temperature is the reaction spontaneous? a. -167 °C b. 298 °C 7500 0= 7.50 + 1+ 70.70 14.70.74 d. -112 °C e. 0 °C 47.50 47.50 C+273=X 7.50 € - 70.79- =

A key component in many chemical engineering designs is the separation of mixtures of chemicals. (a) What happens to the entropy of the system when a chemical mixture is separated? (b) Are designs for chemical separation more likely to rely on spontaneous or nonspontaneous processes?

Define the following: a. spontaneous process b. entropy c. positional probability d. system e. surroundings f. universe

10.104 (a) When a chemical bond forms, what happens to the entropy of the system? (b) Thermodynamically, what allows any bond formation to occur? (c) What do your answers to parts (a) and (b) suggest must be true about the formation of chemical bonds for the octet rule to hold?

For the reaction NO(g)+NO2(g)N2O3(g) , use tabulated thermodynamic data to calculate H and S. Then use those values to answer the following questions. (a) Is this reaction spontaneous at 25°C? Explain your answer. (b) If the reaction is not spontaneous at 25°C, will it become spontaneous at higher temperatures or lower temperatures? (c) To show that your prediction is accurate, choose a temperature that corresponds to your prediction in part (b) and calculate G . (Assume that both enthalpy and entropy are independent of temperature.)

What happens to the entropy of the universe during a spontaneous process?

The reaction CO2(g)+H2(g)CO(g)+H2O(g) is not spontaneous at room temperature but becomes spontaneous at a much higher temperature. What can you conclude from this about the signs of H and S , assuming that the enthalpy and entropy changes are not greatly affected by the temperature change? Explain your reasoning.

Limestone is predominantly CaCO3, which can undergo the reaction CaCO3(s)CaO(s)+CO2(g). We know from experience that this reaction is not spontaneous, yet S for the reaction is positive. How can the second law of thermodynamics explain that this reaction is not spontaneous?

Given the following information at 25C, calculate G at 25C for the reaction 2A(g)+B(g)3C(g) Substance Hf(kJ/mol) S(J/molK) A(g) 191 244 B(g) 70.8 300 C(g) 197 164 a 956 kJ b 956 kJ c 346 kJ d 346 kJ e 1.03 103 kJ

For the reaction at 298 K, 2NO2(g)N2O4(g) the values of H and S are 58.03 kJ and 176.6 J/K, respectively. What is the value of G at 298 K? Assuming that H and S do not depend on temperature, at what temperature is G = 0? Is G negative above or below this temperature?