Final answer:
The chemical that can enhance the speed of detonation but may hinder it when used in excess is ammonium nitrate.
Step-by-step explanation:
The chemical used to make explosives which can enhance the speed of detonation when added in the right amount but hinders the speed of detonation if added in excess is ammonium nitrate. Ammonium nitrate is a common fertilizer, but it can also serve as an oxidizing agent in explosives such as ANFO (Ammonium Nitrate Fuel Oil). When it is mixed with the right fuel, ammonium nitrate can produce a powerful explosion. However, if too much ammonium nitrate is added to the mixture, it can absorb space and reduce the explosive force because there is not enough fuel relative to oxidizer to maintain the explosive reaction.
Historical examples of its use in explosions include the Oklahoma City bombing and the Texas City disaster. Additionally, depending on the conditions, an ammonium nitrate explosion produces nitrogen, carbon dioxide, and water.