Abstract A test and calibration method for isothermal calorimeters equipped with a device for liquid injection and mixing is described. The procedure was developed with special reference to calorimeters operated with heat flow values in the milli-watt range. The investigated reaction was the dissolution of potassium chloride in water at 298 K in the concentration range 56-80 water molecules per KCl entity or molalities of 0.7-1 mol kg-1. The solution enthalpies (ΔsolH) were assessed after electrical calibration and correction for side effects obtained from separate blank measurements. The obtained values were corrected to the state of infinite dilution (ΔsolH∞) at each experimental molality by use of literature values of the relative apparent enthalpy of dilution. The obtained result was 229.6 ± 1.0 J g-1 (n = 16). The solution enthalpy (ΔsolH) as a function of molality in the experimental concentration interval was fitted by a 1-order polynomial resulting in a slope of -12.3 J g-1 mol-1 kg and intercept of 240.5 J g-1. The results are suggested as reference values for validation of calorimeters calibrated electrically or for the purpose of calibration.

中文翻译：

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氯化钾的溶解作为毫瓦范围内等温量热仪的测试过程

摘要 介绍了一种装有液体注入混合装置的等温量热仪的测试和校准方法。该程序是特别参考以毫瓦范围内的热流值运行的热量计而开发的。研究的反应是氯化钾在 298 K 的水中溶解，浓度范围为 56-80 个水分子/KCl 实体或摩尔浓度为 0.7-1 mol kg-1。在电气校准和校正从单独的空白测量中获得的副作用后，评估溶液焓 (ΔsolH)。通过使用相对表观稀释焓的文献值，将获得的值校正为每个实验摩尔浓度的无限稀释状态 (ΔsolH∞)。所得结果为 229.6 ± 1.0 J g-1 (n = 16)。作为实验浓度区间中摩尔浓度的函数的溶液焓 (ΔsolH) 由一阶多项式拟合，得到 -12.3 J g-1 mol-1 kg 的斜率和 240.5 J g-1 的截距。建议将结果作为验证电校准量热计或用于校准目的的参考值。