What is the precent by mass of sulfur in sulfur dioxide?

The question asks you to determine what percent of the total mass of the compound sulfur dioxide (`~SO_2` ) is due to the mass of the S atom.

In order to determine the percent by mass of S in the compound `~SO_2` , we will need to divide the mass of the S atom by the mass of the entire compound, and then multiply our answer by 100 to put it into percent.

Step 1...

The question asks you to determine what percent of the total mass of the compound sulfur dioxide (`~SO_2` ) is due to the mass of the S atom.

In order to determine the percent by mass of S in the compound `~SO_2` , we will need to divide the mass of the S atom by the mass of the entire compound, and then multiply our answer by 100 to put it into percent.

Step 1: Determine the atomic mass of each element from the periodic table.

• Mass of S is 32.065 g

• Mass of O is 15.9994 g

Step 2: Determine the mass of the entire compound. (`~SO_2` )

• Mass of `~SO_2` = (mass of S) + (2 x mass of O):

            (32.065 g) + (2 x 15.9994 g) = 64.064 g

    *Notice that we multiplied the mass of O by two, since there are two O atoms in the compound.

Step 3: Determine the percent by mass of S in `~SO_2` .

• % Mass of S in `~SO_2` = (mass of S/mass of `~SO_2` ) x 100

            (32.065 g/64.064 g) x 100 = 50.052 %

       So, 50.052 % of the mass of `~SO_2` comes from the S atom.

We can also determine the percent of O by mass in `~SO_2` .

• % Mass of O in `~SO_2`= (2 x mass of O/mass of `~SO_2`) x 100

              (2 x 15.9994 g/64.064 g) x 100 = 49.948 %

Notice that when you add together the percent by mass of the O atoms and the percent by mass of the S atom, your answer should equal 100%.

• 50.052 % + 49.948 % =100 %