Question

The empirical formula for trichloroisocyanuric acid, the active ingredient in many household bleaches is OCNCI. The molar mass of this compouund is 232.41 g/mol. What ​is the molecular formula of trichloroisocyanuric acid.

Answer 1

Answer:

These two are equivalent and valid:

       $C_3Cl_3N_3O_3$

       $Cl_3(CN)_3O_3$

Explanation:

The molecular superscripts for each atom in the molecular formula are determined by the number of times that the mass of the empirical formula is contained in the molar mass.

1. Determine the mass of the empirical formula:

$OCNCl$:

Atomic masses:

• O: 15.999g/mol
• C: 12.011g/mol
• N: 14.007g/mol
• Cl: 35.453g/mol

Total mass:

• 15.999g/mol + 12.011g/mol + 14.007g/mol + 35.453g/mol = 77.470g/mol

2. Divide the molar mass by the mass of the empirical formula:

• 232.41g/mol / 77.470g/mol = 3

3. Multiply each superscript of the empirical formula by the previous quotient: 3

       $O_3C_3N__3Cl_3$

Or:

       $C_3Cl_3N_3O_3$

You might also write CN as a group:

          $Cl_3(CN)_3O_3$