Question

A chemist can determine the mass of K in a sample of known mass that consists of either pure K2O or pure K2O2. From this information, can the chemist answer the question of which compound is in the sample?

Answer 1

Yes , the chemist can answer if the compound in K2O or K2O2

The chemical formula and composition of both the compounds is entirely different. The compound K2O2 has an additional molecule of oxygen than K2O and hence will have have higher molecular mass.

In the compound K2O

molecular mass= 2x 39+16 =94

mass ratio of K in compound= 78/94 = 0.830

In the compound K2O2

molecular mass= 2x 39+16X2 =110

mass ratio of K in compound= 78/110 = 0.710

and hence by the required ratio while extracting K , the chemist may know if the compound is K20 or K2O2

If the ratio is anything different from 0.830 and 0.710 then the compund will be something different

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