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Table 6 Uncertainty in atomic mass of lead Metal

From: Evaluation of purity with its uncertainty value in high purity lead stick by conventional and electro-gravimetric methods

Element Atomic mass of lead (g) Uncertainty in weight (g) Distribution Standard uncertainty Combined standard uncertainty
Pb 207.19 0.1 Rectangular 0.1/√3=0.05773 0.0578 (PbSO4)
S 32.065 0.005 Rectangular 0.005/√3=0.00289#
O# 15.9994 0.0003 Rectangular 0.0003/√3=0.00017# =0.00017*4=0.00068
O# 15.9994 0.0003 Rectangular 0.0003/√3=0.00017# =0.00017*2=0.00034 0.0577 (PbO)
  1. In gravimetry lead obtained in the form of PbSO4/ PbO2;
  2. O# four atoms of oxygen have been considered in combined uncertainty for PbSO4 and two atoms have been considered for PbO.