Radioactive tracer such as a cell or tissue, or as a flow tracer to track fluid flow. Radioactive tracers are also used to determine the location of fractures created by hydraulic fracturing in natural gas production. Radioactive tracers form the basis of a variety of imaging systems, such as, PET scans, SPECT scans and technetium scans. Radiocarbon dating uses the naturally occurring carbon-14 isotope as an isotopic label. Isotopes of a chemical element differ only in the mass number. For example, the isotopes of hydrogen can be written as H, H and H, with the mass number at top left. When the
Hydrochloric acid a corrosive effect on human tissue, with the potential to damage respiratory organs, eyes, skin, and intestines irreversibly. Upon mixing hydrochloric acid with common oxidizing chemicals, such as sodium hypochlorite (bleach, NaClO) or potassium permanganate (KMnO), the toxic gas chlorine is produced. Personal protective equipment such as latex gloves, protective eye goggles, and chemical-resistant clothing and shoes will minimize risks when handling hydrochloric acid. The United States Environmental Protection Agency rates and regulates hydrochloric acid as a toxic substance. The UN number or DOT number is 1789. This number will be displayed on a placard on the container. Hydrochloric acid