The first-order rate constant for the decomposition of N2O5,

2N2O5(g)→4NO2(g)+O2(g)

at 70∘C is 6.82×10−3 s−1. Suppose we start with 2.50×10−2 mol of N2O5(g) in a volume of 1.6 L What is the half-life of N2O5 at 70 ∘C ?