Many calculations for science or trade require the evaluation and propagation of measurement uncertainty. Although relative atomic masses (standard atomic weights) of elements in normal terrestrial materials and chemicals are widely used in science, the uncertainties associated with these values are not well understood. In this technical report, guidelines for the use of standard atomic weights are given. This use involves the derivation of a value and a standard uncertainty from a standard atomic weight, which is explained in accordance with the requirements of the Guide to the Expression of Uncertainty in Measurement. Both the use of standard atomic weights with the law of propagation of uncertainty and the Monte Carlo method are described. Furthermore, methods are provided for calculating uncertainties of relative molecular masses of substances and their mixtures. Methods are also outlined to compute material-specific atomic weights whose associated uncertainty may be smaller than the uncertainty associated with the standard atomic weights.

中文翻译：

---

标准原子量的解释和使用（IUPAC 技术报告）

许多科学或贸易计算需要测量不确定度的评估和传播。尽管正常地球材料和化学品中元素的相对原子质量（标准原子量）在科学中被广泛使用，但与这些值相关的不确定性尚不清楚。在本技术报告中，给出了使用标准原子量的指南。这种用途涉及从标准原子量推导值和标准不确定度，根据测量不确定度表达指南的要求进行解释。描述了使用具有不确定性传播定律的标准原子量和蒙特卡罗方法。此外，提供了计算物质及其混合物相对分子质量不确定度的方法。还概述了计算特定材料原子量的方法，其相关不确定性可能小于与标准原子量相关的不确定性。