  Young stars are highly variable in the X-ray regime. In particular, bright
X-ray flares can substantially enhance ionization in the surrounding
protoplanetary disk. Since disk chemical evolution is impacted by ionization,
X-ray flares have the potential to fundamentally alter the chemistry of planet
forming regions. We present 2D disk chemical models that incorporate a
stochastic X-ray flaring module, named \xgen, and examine the flares' overall
chemical impact compared to models that assume a constant X-ray flux. We
examine the impact of 500 years of flaring events and find global chemical
changes on both short time scales (days) in response to discrete flaring events
and long time-scales (centuries) in response to the cumulative impact of many
flares. Individual X-ray flares most strongly affect small gas-phase cations,
where a single flare can temporarily enhance the abundance of species such as
H$_3^+$, HCO$^+$, CH$_3^+$, and C$^+$. We find that flares can also drive
chemistry out of "steady state" over longer time periods, where the
disk-integrated abundance of some species, such as O and O$_2$, changes by a
few percent over the 500 year model. We also explore whether the specific
history of X-ray flaring events (randomly drawn but from the same energy
distribution) impacts the chemical evolution and find that it does not.
Finally, we examine the impact of X-ray flares on the electron fraction. While
most molecules modeled are not highly sensitive to flares, certain species,
including observable molecules, are very reactive to the dynamic environment of
a young star.
