At a certain temperature the rate of this reaction is second order in SO3 with a rate constant of 1.18·M-1s-1 :2SO3(g)--> +2SO2(g) + O2(g)Suppose a vessel contains SO3 at a concentration of 1.33M .

Calculate the concentration of SO3 in the vessel 8.50 seconds later.

You may assume no other reaction is important. Round your answer to 2 significant digits.