TABLE 7.
Contribution of measurement uncertainty in the purity analysis of the original La2O3 sample.
| Uncertainty component | Relative standard uncertainty, % |
|---|---|
| Repeatability of the gravimetric analysis | 0.0080 |
| Stoichiometry of weighing forms | 0.024 |
| Weighing for original La2O3 | 0.00066 |
| Weighing for oxide form | 0.00069 |
| Weighing for sulfate form | 0.00069 |
| Impurities | 0.000019 |
| Molecular weights | |
| La2O3 | 0.00040 |
| La2(SO4)3 | 0.0053 |
| Combined standard uncertainty | 0.026 |
| Coverage factor | 2.18 |
| Expanded uncertainty(U), relative (%) | 0.057 |