Photosynthesis is a chemical reaction that occurs in nature, but one that is generally not thermodynamically favored. It is forced forward by the presence of light. Which of the following is another example of a thermodynamically unfavored process, which must be forced to occur by the use of an external source of energy?
Which of the following combinations of conditions is found to be thermodynamically favored at high temperatures, but unfavored at low temperatures?
Which of the following chemical reactions has a positive ΔS°?
What is true of the absolute entropy values, S°, of all substances?
Given the absolute entropies below, all given in units of J K
-1 mol -1, calculate ΔS° for the formation of NH 3(g) from its elements.
2(g) = 192
S° H 2(g) = 131
S° NH 3(g) = 193
2(g) + 3H 2(g) → 2NH 3(g)
Which situation described below, is the one with the greatest entropy?
Which combination of ΔG°, K and rate of reaction, best describes a thermodynamically favored reaction?
Sodium nitrate is observed to be highly soluble in water under standard conditions. It is also observed that the temperature of the solution drops quite dramatically during the solution process. Which statement best describes these observations and the change in entropy that occurs?
It is found that the reaction below has ΔG° = -35 kJ mol
-1 and ΔH° = -100 kJ mol -1.
2(g) + 3B 2(g) ⇌ 2AB 3(g)
It is also found that when reactants A
2(g) and B 2(g) are mixed in the stoichiometric ratio under standard conditions, no AB 3(g) is formed. What is the best explanation for this observation?
The combustion of a solid hydrocarbon in oxygen, leads to the production of two gases and the evolution of energy. The reaction is found to be thermodynamically favored. What is the driving force for this reaction?