Category: Chemical Engineering Math
"Published in Vacaville, California, USA"
The tip of the head of a strike anywhere match contains a phosphorus-sulfur compound that readily ignites when drawn over a rough surface. What is the empirical formula of this ignitable compound given that a sample of the compound contains 0.5629 g of phosphorus and 0.4371 g of sulfur?
(Molecular Weights: P = 31, and S = 32)
Solution:
Moles of each components:
Moles of phosphorus is
Moles of sulfur is
From
the number of moles of each component, we need to divide all of them by
their least number of moles which is sulfur in order to get the number
of atoms in a sample.
Number of phosphorus in a sample is
Number of sulfur in a sample is
Since
the number of atoms for phosphorus is a fraction which is 4/3, then we need
to multiply all the atoms by 3 so that the number of atoms for
empirical formula are all whole numbers. Therefore, the empirical
formula for a strike anywhere match is