S + O2 --> So2. P = 101kPa = 1atm. R = 0.082 atm - L - (mol-K)^-1. Applying ideal gas equation PV = nRT. n = 1x4.5/0.082x573 = 0.096mole. According to stoichiometry, moles of S = moles of SO2 = 0.096mol. Mass of S = moles of So2 x molar Wt = 0.095x32 = 3.04moles. Hope it helps
