Complex sentence: Carbonated drinks, more specifically Diet Coke, contain Carbon Dioxide can causes quite violent reactions in certain situations, and when combining with Mentos and Diet Coke it has one of the most intense reactions.
Split into simpler sentences: Carbonated drinks, more specifically Diet Coke, contain Carbon Dioxide, which can causes quite violent reactions in certain situations. Combining Mentos and Diet Coke has one of the most intense reactions.