Question

Calculate the emprical formula of a compound having percentage composition potassium 27.57%,chorimium 35.36%,oxygen 84.07%

Answer 1

Explanation:

Find out the mass of each element by assuming an overall mass of the elements. Eg 100

∴ the masses of the elements will be 27. 57 g, 35.36g, and 84.07g for K, Cr, and O respectively.

Now convert these masses into moles by dividing them

by molecular mass.

27.57/39 = 0.70

35.36/52 = 0.68

84.07/16 = 5.2

Divide the moles by smaller mole unit i.e 0.68

0.70/.68 = 1

0.68/0.68 = 1

5.2/0.68 = 7

∴ the emperical formula will be KCrO₇