Question

Consider that a sample of a compound is decomposed and the masses of its constituent elements is as follows: 1.443 g Se, 0.5848 g O What would be the empirical formula for this compound?

Answer 1

Answer: The empirical formula is
`SeO_2`.

Step-by-step explanation:

So, the mass of each element is given:

Mass of Se = 1.443 g

Mass of O = 0.5848 g

Step 1 : convert given masses into moles.

Moles of Se=
`\frac{\text{ given mass of Se}}{\text{ molar mass of Se}}= (1.443g)/(79g/mole)=0.018moles`

Moles of O =
`\frac{\text{ given mass of O}}{\text{ molar mass of O}}= (0.5848g)/(16g/mole)=0.036moles`

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For Se =
`(0.018)/(0.018)=1`

For O =
`(0.036)/(0.018)=2`

The ratio of Se: O = 1: 2

Hence the empirical formula is
`SeO_2`.