冰点降低法测定煤油的平均相对分子质量
任春波,沈兆欣,吴庆元,张静林
北京航天计量测试技术研究所,北京 100076
Determination of average relative molecular mass of kerosene by cryoscopic method
任春波,沈兆欣,吴庆元,张静林
Beijing Aerospace Institute of Metrology and Measurement, Beijing 100076, China
摘要:基于稀溶液体系的依数性原理,建立了冰点降低法测定煤油的平均相对分子质量。采用苯作为溶剂,通过对溶液浓度、冰点降低值的系统考察,确定了煤油在苯溶液中的最佳含量为小于15 g/kg。试验结果表明,该方法用于煤油相对分子质量的测定,在99%置信度下,10次重复测定结果的G值最大值为1.872,小于临界值;5个平行试样测定结果的标准偏差为0.708 g/mol,变异系数为0.0044%;测定值与计算值的相对误差在±1%之内。该方法简单、可靠,具有良好的重复性、精密度和准确性。
Abstract:Based on the principle of number dependence of dilute solution system, a method for determining the average relative molecular mass of kerosene by crioscopic method was established. Using benzene as the solvent, the optimum content of kerosene in benzene solution was less than 15 g/kg through the systematic investigation of the concentration of solution and the reduction of freezing point. Test results showed that with the crioscopic method, the maximum value of the G value of the 10 repeated results was 1.872 under the confidence of 99%, which was less than the critical value. The standard deviation of 5 parallel specimens was 0.708 g/mol, the difference coefficient was 0.0044%, and the relative error of the caculated value was within ±1%. This method is simple, reliable, and it has good repeatability, precision and accuracy.
关键词:煤油;平均相对分子质量;冰点降低法
Keywords:kerosene; average relative molecular mass; crioscopic method
本文引用格式:
任春波,沈兆欣,吴庆元,等.冰点降低法测定煤油的平均相对分子质量[J].化学分析计量,2018,27(3):32-35.
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