A Student performs a kinetic experiment on the first-order kinetics of the reaction: N2O4 -> 2NO + O2. She calculates the first-order rate constant k= 0.750 s-1 and the following data: intitial mass of N2O4: 25.7 ± 0.3 g, initial volume of N2O4: 0.22 ± 0.01 L, and time t = 3.8 ± 0.2 s. Use error analysis yo calculate her reported concentration of N2O4 including the range of uncertainty.