how many grams of phosphorus (P4) react with 35.5L of O2 at STP to form solid tetraphosphorus decaoxide

mass P4 = 35.998 g

Explanation:

P4 + 5O2 → P4O10

∴ STP: P = 1 atm; T = 298 K

∴ V O2 = 35.5 L

⇒ nO2 = P. V / R. T

∴ R = 0.082 atm. L/K. mol

⇒ nO2 = ((1 atm) * (35.5L)) / ((0.082 atm. L/K. mol) (298K))

⇒ nO2 = 1.453 mol O2

⇒ mol P4 = (1.453 molO2) * (mol P4 / 5molO2) = 0.2906 mol P4

∴ Mw P4 = 123.895 g/mol

⇒ mass P4 = (0.2906 mol P4) * (123.895 g/mol) = 35.998 g P4