It looks like you're new here. If you want to get involved, click one of these buttons!
Classical computers aren’t that good at simulating chemical reactions. For instance, accurately computing the energies of the propane molecule (C3H8) takes ten days with a classic computer design. Molecular systems use highly-entangled superposition states, which require exponentially more computing resources to represent them sufficiently with high precision.
If it takes up to ten days to represent a single molecule with high precision, then representing thousands (or millions) of molecules at the same time, and how they react with each other, becomes an almost impossible task with a classic computer architecture. It is also a highly inefficient process in terms of energy use. Chemical reactions seem to work at a quantum level, so quantum computers are ideal for trying to simulate them as efficiently and as accurately as possible.