CHE 2B Midterm: Practice for Professor Donadio's upcoming exam :)

5. When 1 mole of Fe20s(s) reacts with H2(g) to form Fe(s) and HO(g) according to the following equation, 98.8 kJ of energy are absorbed. Feo,(s) + 3 H2(g) → 2 Fe(s) + 3 H2O(g) Reactants Products AH Products Reactants Is the reaction endothermic or exothermic, and which of the enthalpy diagrams above represents this reaction? a. endothermic, A b. endothermic, B c. exothermic, A d. exothermic, B

Use the data given to calculate the value of delta G^o _rxn at 25 degree C for the reaction given below. delta G degree _f for CO(-137.16 kJ/mol. C(graphite) + 1/2 O_2(g) rightarrow CO(g) +137.16 kJ -68.58 kJ -137.16 kJ +274.32 kJ -27432 kJ At what temperature or range of temperatures will a reaction be spontaneous if the value of delta H degree = +42 delta S degree = +331.5 J/K? temperatures between 42.8 K and 331.5 K all temperatures below 129 K all temperatures above 7.75 K the reaction is never spontaneous. all temperatures above 129 K Which group contains only solutes that would decrease the solubility of barium sulfate? Na_2 SO_4, NaOH, NaCH_3 COO HNO_3, H_2 SO_4, HCH_3 COO Ba(OH)_2, NaOH, NH_4 OH Ba(NO_3)_2, Na_2 SO_4, H_2 SO_4 SO_2, CO_2, NH_3 Which set of conditions describes a reaction that is most likely to proceed? exothermic, increasing entropy, low activation energy exothermic, decreasing entropy, high activate energy endothermic, decreasing entropy, low activation energy endothermic, decreasing entropy, high active energy exothermic, increasing entropy, high activation energy A certain reaction has delta H degree _rxn = +177.8 kJ, and delta S degree _rxn = +160.5 J/K. Above what temperature does it product-favored? 630 degree C 1108 degree C 1381 degree C 384 degree C 835 degree C

Energy that is associated with the position or composition of an object is called a. kinetic energy b. thermal energy c. potential energy d. chemical energy Choose the reaction that illustrates Delta H degree f for NaHCO_3. a. Na(s) + H_2(g) + C(s) + O_2(g) rightarrow NaHCO_3 (s) b. Na^+ (aq) + HCO_3^- (aq) rightarrow NaHCO_3 (s) C. Na^+ (aq) + H_2O (l) + CO_2 (g) rightarrow NaHCO_3(s) d. Na(s) + 1/2 H_2 (g) + C(s) + 3/2 O_2 (g) rightarrow NaHCO_3 (s) e. Na(s) + 2 H(g) + C(s) + 3 O(g) rightarrow NaHCO_3 (s) Use the standard reaction enthalpies given below to determine Delta H degree _rxn for the following reaction: 4SO_2 (g) rightarrow 4 S(s) + 6 O_2 (g) Delta H degree _rxn = ? Given: SO_2 (g) rightarrow S(s) + O_2 (g) Delta H degree _rxn = +296.8 kJ 2 SO_2 (g) + O_2 (g) rightarrow 2 SO_3 (g) Delta H degree _rxn = -197.8 kJ a. -494.6 kJ b. -692.4 kJ c. -791.4 kJ d. 1563 kJ e. -293.0 kJ A piece of iron (mass = 25.0 g) at 398 K is placed in a Styrofoam coffee cup containing 25.0 mL of water at 298 K. Assuming that no heat is lost to the cup or the surroundings, what will the final temperature of the water be? The specific heat capacity of iron = 0.499 J/g degree C and water = 4.18 J/g degree C. a. 348 K b. 308 K c. 287 K d. 325 K e. 388 K