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
Precipitation (chemistry) processes are often used in sequence – for example, a barium nitrate solution will react with sulfate ions to form a solid barium sulfate precipitate, indicating that it is likely that sulfate ions are present. Digestion, or "precipitate ageing", happens when a freshly formed precipitate is left, usually at a higher temperature, in the solution from which it precipitates. It results in cleaner and bigger particles. The physico-chemical process underlying digestion is called Ostwald ripening. Precipitation (chemistry) Precipitation is the creation of a solid from a solution. When the reaction occurs in a liquid solution, the solid formed is called