This work reports the first use of rubber latex waste as the hydrophobic reagent for a low-cost, simple, and rapid fabrication of a paper towel-based experimental device (PTED) with a circular design of 5 mm to demonstrate the factors affecting chemical equilibrium; this serves as a user-friendly means for a laboratory experiment. The illustration of the factors affecting chemical equilibrium is implemented in the PTED. In this approach, the color change of a cobalt(II) complex reaction from pink to blue was observed by the naked eye on the PTED when a tiny drop of hydrochloric acid solution and the treatment of heat by using a hot air dryer (1200 W, 2 min) were applied to the PTED with the precoated cobalt solution (pink color), separately or together. The return of the color of the reactions from blue to pink was carried out by using a tiny drop of water and the treatment of cooling by using an ice bath for 10 min. In addition, the chemical equilibrium constant (K_c) can be easily quantified by processing digital images of the detection zones of PTED captured with a smartphone camera under a control light box at room temperature (≈25 °C), while image analysis was performed using ImageJ software. This PTED laboratory is a new approach not only to enhance students’ learning of the factors affecting chemical equilibrium based on Le Châtelier’s principle, but also to present potential applications of PTED into all levels of chemistry from middle school through college classes.

中文翻译：

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制造低成本，简单，丝网印刷的纸巾为基础的实验设备，以证明影响化学平衡和化学平衡常数，K _c的因素

这项工作报告了首次使用橡胶乳胶废料作为疏水剂，以低成本，简单，快速地制造基于纸巾的实验装置（PTED），其圆形设计为5毫米，以证明影响化学平衡的因素; 这是用于实验室实验的用户友好方式。在PTED中对影响化学平衡的因素进行了说明。在这种方法中，当一滴盐酸溶液滴入PTED并通过使用热空气干燥器（1200 W）进行热处理时，用肉眼在PTED上观察到钴（II）络合物从粉红色变为蓝色的颜色变化。分别用2分钟）或预涂的钴溶液（粉红色）涂到PTED上。用一小滴水使反应的颜色从蓝色变为粉红色，并用冰浴冷却10分钟进行冷却。另外，化学平衡常数（通过使用智能手机相机在室温（≈25°C）的控制灯箱下处理智能手机相机捕获的PTED检测区域的数字图像，可以轻松量化K _c），同时使用ImageJ软件进行图像分析。这个PTED实验室不仅是一种新方法，不仅可以提高学生对基于LeChâtelier原理的化学平衡影响因素的学习，而且可以展示PTED在从中学到大学课程的所有化学水平中的潜在应用。