用 1 mol 理想气体进行焦耳实验(自由膨胀)，求得 ΔS = 19.16 J/K，则体系的吉布斯自由能变化为A:ΔG = 19.16 J B:ΔG < 19.16 J C:ΔG > 19.16 J D:ΔG = 0 答案: ΔG < 19.16 J