58. Solution to Chemistry Problem

2. For nephelometric determination of sulfur in coal, 0.0100 M H2SO4 was used as a standard. In this case, 2.50 ml of it was diluted to 1000.0 ml, from V ml of the resulting solution, a BaSO4 suspension was prepared in a 100.0 ml flask and after bringing it to the mark, the apparent optical density was measured. A calibration graph was constructed based on the data obtained:
V, ml 20.0 15.0 12.0 8.0 4.0 2.0
Ac 0.210 0.330 0.420 0.600 0.800 0.920
100.0 ml of solution was prepared from a sample of coal weighing m g, 20.0 ml of it was placed in a measuring flask with a capacity of 250.0 ml, a BaSO4 suspension was prepared and brought to the mark. Determine the mass fraction (%) of sulfur in coal if the apparent optical density was:
Option 1 2 3 4
m,g = 0.1348 1.832 0.1008 0.1212
Ac = 0.46 0.30 0.69 0.54
SOLUTION FOR ALL 4 OPTIONS