<h3>Answer:</h3>
482.596 grams
<h3>Explanation:</h3>The relationship between moles, molar mass and mass of a compound is given by;
In this case;
The compound in question is P₂O₅
Molar mass of P₂O₅ = 141.94 g/mol
Rearranging the formula;
Mass = Moles × molar mass
Therefore;
Mass of P₂O₅ = 3.4 mol × 141.94 g/mol
= 482.596 grams
Therefore, mass of P₂O₅ is 482.596 grams