a. What is the Gibbs free energy at 298 K for this reaction? \mathrm{C}(\mathrm{s})+2 \mathrm{H}_{2}(g) \rightarrow \mathrm{CH}(g) \Delta H=-74.85 \mathrm{~kJ} / \mathrm{mol} \Delta S=-0.08084 \mathrm{~kJ} /(\mathrm{mol} \cdot \mathrm{K}) Is the reaction spontaneous at 298 K (room temperature)? (3 points) b. When NaCl (table salt) dissolves in water, the change is endothermic. Yet, when added to water, it dissolves without added energy (spontaneously) over a wide range of temperatures.How can this be? (2 points) c. The reaction Br,() → Br,(g) has a AH = 30.91 kJ and AS = 0.0933 kJ/K. At what temperature does this reaction become spontaneous? Below this temperature, is the forward reaction or the backward reaction favored? (3 points) d. People use propane as fuel for their BBQ grills. The combustion of propane is highly spontaneous at all temperatures. What keeps BBQ grills from catching fire the minute they're turned on? (2 points)

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