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.

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.