When acids and bases are mixed together, it causes a reaction, which is a type of reaction. ORGANIC COMPOUNDS - All organic compounds contain , with the exception of carbon monoxide and carbon dioxide. - Carbon is classified as _ meaning it never gains or loses_, it just shares them. It forms four bonds with other elements. - The four major organic compounds are: and - Many organic compounds are classified as being _, which are chains of smaller building block units called These compounds are formed by and broken down by.