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用N_2O_4-NO_2体系做压强对化学平衡影响 的演示实验,已发表多篇文章,有的意见还 值得商榷。 一、影响体系颜色的因素 ΔG_f~o(千焦/摩)98.29 51.84 ΔH_f~o(千焦/摩)9.66 33.85 N_2O_4解离是吸热反应,在25℃时吸热为58.04千焦耳。升高温度化学平衡向着生成NO_2的方向移动,当温度达140℃时,N_2O_4完全解离,体系呈褐色。当温度降低时,化学平衡向生成N_2O_4的方向移动。当N_2O_4和NO_2分压之和
The N 2 O 4 -NO 2 system was used as a demonstration experiment for the effect of pressure on chemical equilibrium. Many articles have been published, and some opinions are still open to question. I. Factors influencing the color of the system ΔG_f~o (kJ/m) 98.29 51.84 ΔH_f~o (kJ/m) 9.66 33.85 The dissociation of N_2O_4 is an endothermic reaction and the endotherm is 58.04 kJ at 25°C. The chemical equilibrium at elevated temperature moves towards the direction of NO_2 production. When the temperature reaches 140°C, N_2O_4 dissociates completely and the system becomes brown. When the temperature decreases, the chemical equilibrium shifts towards the generation of N2O4. When the sum of partial pressures of N_2O_4 and NO_2