This study explores plasma assisted pentane oxidation and pyrolysis in a nanosecond pulsed discharge using laser absorption spectroscopy and gas chromatography. An updated pentane model is developed with C0-C2 substitution by HP-Mech, plasma chemistry sub-mechanism, and new electron impact dissociation reactions added. Using temperature as a model input, the electron impact cross sections of pentane are adjusted so the model accurately predicts the pyrolysis steady state and time-dependent species profiles, and then tested on the oxidation case. Results show favorable prediction of pentane consumption and H2O and CH2O formation. CH4 is slightly under-predicted by the new model, while C2H2 is overpredicted, likely due to under-consumption, perhaps by radicals such as OH. The addition of electron impact dissociation reactions slows the overall oxidative pathway by a reduction in OH concentration and prevents over-prediction by adjusting the branching ratio towards smaller hydrocarbons instead of oxidative species.