Consider the chemical equation and equilibrium constant for the synthesis of sulfur trioxide at 100°C: N₂O4 (g) Calculate the equilibrium constant for the following reaction at 100°C: 2NO₂ (g) 2NO₂ (g) K = 0.212 N₂O4 (g)

Adenosine triphosphate, ATP, is used as a free-energy source by biological cells. (See the essay on page 624.) ATP hydrolyzes in the presence of enzymes to give ADP: ATP(aq)+H2O(l)ADP(aq)+H2PO4(aq);G=30.5kJ/molat25C Consider a hypothetical biochemical reaction of molecule A to give molecule B: A(aq)B(aq);G=+15.0kJ/molat25C Calculate the ratio [B]/[A] at 25C at equilibrium. Now consider this reaction coupled to the reaction for the hydrolysis of ATP: A(aq)+ATP(aq)+H2O(l)B(aq)+ADP(aq)+H2PO4(aq) If a cell maintains a high ratio of ATP to ADP and H2PO4 by continuously making ATP, the conversion of A to B can be made highly spontaneous. A characteristic value of this ratio is [ATP][ADP][H2PO4]=500 Calculate the ratio [B][A] in this case and compare it with the uncoupled reaction. Compared with the uncoupled reaction, how much larger is this ratio when coupled to the hydrolysis of ATP?

1. A process is spontaneous in the direction that moves it away from equilibrium toward equilibrium

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.