if 96g so2 is added to 2 moles of oxygen at stp, what is the mass of so3 that is formed

Answer 1

2SO2 + O2 ==> 2SO3

mols SO2 = g/molar mass = ?
Using the coefficients in the balanced equation, convert mols SO2 to mols SO3.
Now convert mols SO3 to g. g = mols x molar mass.

Answer 2

n=m/M
=m.M
=80g.mol.1,5mol
=120g