Which of the following is true for pure oxygen gas, O₂(g) at 25°C? A)Δ H° _f 0 B)Δ H° _f 0 D)Δ G° _f 0

Question

Which of the following is true for pure oxygen gas, O₂(g) at 25°C? A)Δ H° _f > 0 B)Δ H° _f < 0 C)Δ G° _f > 0 D)Δ G° _f < 0 E)S° > 0

Quizplus · Accepted Answer

For pure substances in their standard states, such as oxygen gas (O2) at 25°C, the standard enthalpy of formation (ΔH°f) is defined as zero because it is in its most stable form at this condition. The standard Gibbs free energy of formation (ΔG°f) is also zero under standard conditions for elements in their stable forms. However, the standard entropy (S°) for any substance is always greater than zero because all substances possess some degree of molecular motion and disorder at temperatures above absolute zero (0 K), including pure oxygen gas.

Which of the Following Is True for Pure Oxygen Gas