One example of chemical reactions that may harm fossils is the changes that can occur in iron pyrite (FeS2). The sulfide component oxidizes to FeSO4 in the presence of oxygen, which leads to the production of sulfuric acid (H2 SO4) if water (H2O) is available. A simplified reaction is shown below: 4FeS2 + 13O2 + 2H2O - 4FeSO4 + 2H2 SO4+ 2SO2 This reaction is more commonly observed where the pyrite occurs in microcrystals. The resulting 'decay' is marked by yellow-white efflorescences, cracking of the specimen, sulfurous odor, and scorched boxes or labels where they come in contact with the reacting specimen.
to undergo a chemical change. For instance, flames from a fire react with the wood to form smoke, and eventually you are left with ash or charcoal instead of wood. This is a chemical change that happened because the wood reacted with the fire. NOx and VOCs react to form ozone. Ozone can react in a similar way with rubber, plants, and our lungs to cause them to break down. (Back to Ozone Action! Days)
To act in response to something. For example, a chemical can change, or react, if added to another chemical.
React was established in 1990 as an English electronic dance music record label based in Putney, London.