Question

A 3.78 g sample of a blue-colored powder contains 1.52 g of chromium, 0.88 g of sulfur and 1.38 g of oxygen.
What is the Empirical formula of the compound?

Answer 1

Answer:

CrSO₃

Explanation:

Given parameters:

Mass of sample  = 3.78g

Mass of chromium  = 1.52g

Mass of sulfur = 0.88g

Mass of oxygen  = 1.38g

Unknown:

Empirical formula of the compound  = ?

Solution:

The empirical formula of a compound is the simplest formula of such a compound.

To solve this problem, follow the chart below:

Elements                           Cr                            S                       O

Mass                                1.52                         0.88                   1.38

Molar mass                       52                            32                      16

Number of moles           1.52/52                     0.88/32            1.38/16

                                        0.029                       0.028               0.086

Divide through by

the smallest                0.029/0.028            0.028/0.028       0.086/0.028

                                             1                                  1                          3

So,

The empirical formula is   CrSO₃