Problem 49
At \(25^{\circ} \mathrm{C}, \Delta G^{\circ}\) for the process: $$ \mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons \mathrm{H}_{2} \mathrm{O}(g) $$ is \(8.6 \mathrm{~kJ} / \mathrm{mol} .\) Calculate the vapor pressure of water at this temperature.
Problem 51
What is a coupled reaction? What is its importance in biological reactions?
Problem 52
What is the role of ATP in biological reactions?
Problem 54
In the metabolism of glucose, the first step is the conversion of glucose to glucose 6 -phosphate: glucose \(+\mathrm{H}_{3} \mathrm{PO}_{4} \longrightarrow\) glucose 6 -phosphate \(+\mathrm{H}_{2} \mathrm{O}\) $$ \Delta G^{\circ}=13.4 \mathrm{~kJ} / \mathrm{mol} $$ Because \(\Delta G^{\circ}\) is positive, this reaction does not favor the formation of products. Show how this reaction can be made to proceed by coupling it with the hydrolysis of ATP. Write an equation for the coupled reaction, and estimate the equilibrium constant for the coupled process.
Problem 55
Predict the signs of \(\Delta H, \Delta S,\) and \(\Delta G\) of the system for the following processes at 1 atm: (a) ammonia melts at \(-60^{\circ} \mathrm{C},(\mathrm{b})\) ammonia melts at \(-77.7^{\circ} \mathrm{C},(\mathrm{c})\) ammonia melts at \(-100^{\circ} \mathrm{C}\). (The normal melting point of ammonia is \(-77.7^{\circ} \mathrm{C}\).)
Problem 57
Which of the following thermodynamic functions are associated only with the first law of thermodynamics: \(S, U, G,\) and \(H ?\)
Problem 58
A student placed \(1 \mathrm{~g}\) of each of three compounds \(\mathrm{A}, \mathrm{B}\) and \(\mathrm{C}\) in a container and found that after 1 week no change had occurred. Offer some possible explanations for the fact that no reactions took place. Assume that \(\mathrm{A}\), B, and \(C\) are totally miscible liquids.
Problem 59
Consider the following reaction at \(298 \mathrm{~K}:\) $$ 2 \mathrm{H}_{2}(g)+\mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{H}_{2} \mathrm{O}(l) \quad \Delta H^{\circ}=-571.6 \mathrm{~kJ} / \mathrm{mol} $$ Calculate \(\Delta S_{\mathrm{svs}}, \Delta S_{\text {surr }}\), and \(\Delta S_{\text {univ }}\) for the reaction.
Problem 60
Consider the following facts: Water freezes spontaneously at \(-5^{\circ} \mathrm{C}\) and \(1 \mathrm{~atm},\) and ice has a lower entropy than liquid water. Explain how a spontaneous process can lead to a decrease in entropy.
Problem 61
Ammonium nitrate \(\left(\mathrm{NH}_{4} \mathrm{NO}_{3}\right)\) dissolves spontaneously and endothermically in water. What can you deduce about the sign of \(\Delta S\) for the solution process?
