An atmospheric chemist studying SO2 places a mixture of SO2 and O2 in a 2 L container at 800 K and 1.90 atm. When the reaction occurs, SO3 forms and pressure falls to 1.65 atm. How many moles of SO3 formed?

a) 0.086 mol
b) 0.104 mol
c) 0.128 mol
d) 0.152 mol