Example 8.6 • A sample of slag from a blast furnace is analyzed for SiO2 by decomposing a 0.5003 g sample with HCI, leaving a residue with a mass of 0.1414 g. After treating with HF and H2SO4 and evaporating the volatile SiF4, a residue with a mass of 0.0183 g remains. Determine the %w/w SiO2 in the sample.