8. Calculate K for the following reaction run at 25°C: C(s) + CO2(g) → 2 CO(g) Substance So J/(mol-K) C(s) 5.7 CO2(g) 214 CO(g) 19 AH°+ (kJ/mol) 0 -394 -110

For each reaction, an equilibrium constant at 298 K is given. Calculate G for each reaction. (a) H+(aq) + OH-(aq)H2O Kc = 1.0 1014 (b) CaSO4(s)Ca2+(aq) + SO42 (aq) Kc = 7.1 105 (c) HIO3(aq)H+(aq) + IO3 (aq) Kc = 1.7 101

Consider the reaction H2(g)+Br2(g)2HBr(g) where H = 103.8 kJ/mol. In a particular experiment, equal moles of H2(g) at 1.00 atm and Br2(g) at 1.00 atm were mixed in a 1.00-L flask at 25C and allowed to reach equilibrium. Then the molecules of H2 at equilibrium were counted using a very sensitive technique, and 1.10 1013 molecules were found. For this reaction, calculate the values of K, G, and S.

A process that is reactant-favored at equilibrium can never be spontaneous. This statement is (a) true (b) false

9.96 Most first aid "cold packs" are based on the endothermic dissolution of ammonium nitrate in water: NH4NO3(s)NH4+(aq)+NO3(aq) H= 25.69 kJ A particular cold pack contains 50.0 g of NH4NO3 and 125.0 g of water. When the pack is squeezed, the NH4NO3dissolves in the water. If the pack and its contents are initially at 24.0°C, what is the lowest temperature that this bag could reach? (Assume that the ammonium nitrate solution has a specific heat of 4.25J g-l K-l, and that the heat capacity of the bag itself is small enough to be neglected.)

Consider the equation G = G + RT ln(Q). What is the value of G for a reaction at equilibrium? What does Q equal at equilibrium? At equilibrium, the previous equation reduces to G = RT ln(K). When G 0, what does it indicate about K? When G 0, what does it indicate about K? When t G = 0, what does it indicate about K? G predicts spontaneity for a reaction, whereas G predicts the equilibrium position. Explain what this statement means. Under what conditions can you use G to determine the spontaneity of a reaction?

Consider the decomposition of CaCO3(s) into CaO(s) and Co2(g). What is the equilibrium partial pressure of CO2 at room temperature?

Organ pipes in unheated churches develop tin disease, in which white tin is converted to gray tin. Given white Sm: H f =0.00 kJ/mol; S =51.55 J/mol K gray Sn: H f =2.09 kJ/mol; S =44.14 J/mol K calculate the equilibrium temperature for the transition.

Hydrogen gas and iodine gas react to form hydrogen iodide. If 0.500 mol H2 and 1.00 mol I2 are placed in a closed 10.0-L vessel, what is the mole fraction of HI in the mixture when equilibrium is reached at 205C? Use data from Appendix C and any reasonable approximations to obtain K.

Heating some metal carbonates, among them magnesium carbonate, leads to their decomposition. MgCO3(s) MgO(s) + CO2(g) (a) Calculate rG and rS for the reaction. (b) Is the reaction product-favored at equilibrium at 298 K? (c) Is the reaction predicted to be product-favored at equilibrium at higher temperatures?