Amalgam (chemistry) with copper. A nitric acid solution of salts under investigation is applied to a piece of copper foil, and any mercury ions present will leave spots of silvery-coloured amalgam. Silver ions leave similar spots but are easily washed away, making this a means of distinguishing silver from mercury. The redox reaction involved where mercury oxidizes the copper is: Dental amalgam has been studied and is generally considered to be safe for humans, though the validity of some studies and their conclusions have been questioned. Amalgam (chemistry) An amalgam is an alloy of mercury with another metal, which may be a
Sparging (chemistry) Sparging (chemistry) In chemistry, sparging, also known as gas flushing in metallurgy, is a technique which involves bubbling a chemically inert gas, such as nitrogen, argon, or helium, through a liquid. This can be used to remove dissolved gases (e.g. oxygen) from the liquid. By Henry's law, the amount of dissolved gases in a liquid depend on the partial pressure of the gases exposed to the liquid. Sparging increases the gas-liquid interface. Solvents used in high-performance liquid chromatography (HPLC) are often sparged with helium. In biochemical engineering, sparging can also be a method to remove low-boiling liquids from a solution.