Consider the formation of nitrogen dioxide from nitric oxide and oxygen: 2NO(g) + O2(g) --> 2NO2(g). If 9.0 L of NO are reacted with excess O2 at STP, what is the volume in liters of the NO2 gas produced? (Recall that the gas constant, R, = 0.082057 L-atm/mol-K). Please show work.