Question

For the decompostion of gaseous dinitrogen pentaoxide, 2N2O5(g)--->4NO2(g) +O2(g) . The rate constant is k=2.8 x 10^-3 at 60 degrees C. The initial concentration of N2O5 is 2.45 mol/L.

What is (N2o5) after 5.00 min?

What fraction of the N2o5 has decomposed after 5 min?

Answer 1

You omitted the units for the rate constant. It's a first order reaction.
ln(No/N) = kt
No = 2.45 mol
N = ?
k from above
t = 5 min but since k is per second, 5 minutes must be converted to seconds.