DRAFT: This module has unpublished changes.

Mass of the dried precipitate from the mass of the empty crucible and the mass of the crucible with the dried precipitate:

 

37.8356 g - 37.1929 g = 0.6427 g

 

The number of moles of precipitate from its mass and formula weight:

 

0.6427 g  x 1 mol BaSO4    = 0.0028 mol BaSO4

    1         233.4 g BaSO4

 

The number of moles of sulfate ions in the precipitate from the number of moles of precipitate:

 

0.0028 mol SO42-

 

The moles of SO42- are equal to the moles of BaSO4.

 

The mass of the sulfate ions form the number of moles of sulfate ions:

 

0.0028 mol  x (96.1 gSO42-)   = 0.26898 g SO42-

                     (1 mol SO42-) 

 

The theoretical percentage of sulfate content in the unknown sulfate sample based on the mass of the sulfate ions and the total mass of the sample:

 

(0.26898 g SO42-)  x 100 = 76.9%

      (0.35 g)

 

The percent error based on the experimental value of the percent sulfate content of the sample and the percent sulfate content of the proposed unknown:

 

 (79.806 % MgSO4 – 76.9 % SO42-)  x 100 = 3.78% error

                 (76.9% SO42-) 

 

DRAFT: This module has unpublished changes.