The evaporation of a 130−nm film of n-pentane If the initial surface coverage is 8.7×10¹⁶ molecules /cm², how long will it take for one-half from a single crystai of aluminum oxide was found of the film to evaporate? to be zero order with a rate constant of 1.92×10¹³ molecules /cm²- s at 120 K. Part B What fraction of the film will be left after 12 s ?