A 13 g sample of P4010 contains how many molecules of phosphorus pentaoxide?
Answer in units of molec.

Explanation:

You must calculate the moles of P₄O₁₀, convert to moles of P₂O₅,  then convert to molecules of P₂O₅.

1. Moles of P₄O₁₀

2. Moles of P₂O₅

P₄O₁₀ ⟶ 2P₂O₅

The molar ratio is 2 mol P₂O₅:1 mol P₄O₁₀

3. Molecules of P₂O₅

a corroding iron, if that's one of your choices

i think it's letter a.