At a certain temperature this reaction follows second-order kinetics with a rate constant of 1.53 M^-1 . s^-1:
ClCH2CH2Cl(g) → CH2CHCl(g) + HCl(g)
Suppose a vessel contains ClCH2CH2Cl at a concentration of 1.38 M. Calculate the concentration of ClCH2CH2Cl in the vessel 1.90 seconds later. You may assume no other reaction is important.
Round your answer to 2 significant digits.