Complex sentence: A chlorine bomb is a term used to identify a pressurised cannister filled with a reactive substance that a chlorine tablet is added to, this produces an expansive pressure increase usually shattering the container as the chlorine and other gas substances attempt to escape.
Split into simpler sentences: A chlorine bomb is a pressurised cannister filled with a reactive substance. When a chlorine tablet is added, it produces an expansive pressure increase, usually shattering the container as the chlorine and other gas substances attempt to escape.