When Potassium Metal Is Exposed to Air, It Forms a Coating

Short Answer

When potassium metal is exposed to air, it forms a coating of potassium oxide, according to the following equation: 4K(s)+ O₂(g)→ 2K₂O(s)If a piece of potassium gains 0.354 g, assuming this gain can be attributed to the above reaction with oxygen, what mass of potassium reacted? Report your answer with the correct number of significant figures and correct units.