19. The reaction 2NOBr (g) → 2 NO (g) + Br2 (g) is a second-order reaction with a rate constant of 0.80 M-1s-1 at 11 °C. If the initial concentration of NOBr is 0.0440 M, the concentration of NOBr after 6.0 seconds is ________. A) 0.0276 M B) 0.0324 M C) 0.0363 M D) 0.0348 M E) 0.0402 M