Why are silver bracelets white when burned at high temperature?

Silver is one of the metals known and used in ancient times, and it is an important precious metal. Silver exists in the form of simple substance in nature, but most of it exists in silver mines in the form of bound state.

Pure silver is metallic silver, and its content is close to 100%. However, because silver is an active metal, it is easy to react with sulfur in the air to produce silver sulfide, which turns it black, so it is difficult to live in life. Pure silver? Generally, it refers to 99.99% silver or 92.5% 925 pure silver. A real sterling silver ring will only change color if it is burned, and it is not difficult to turn white. Just go home and get some toothpaste brushes. It turns out that the real 925 pure silver will change color after burning, because the surface of silver is easily oxidized at high temperature, and then it will turn black, but it doesn't matter if it is brushed with toothpaste, because the toothpaste contains CACO3 and calcium carbonate, which react with the blackened silver surface to generate CAO and water, so that the chemicals will be washed away immediately after entering the water? Turn black? Yes So please don't worry if you buy silver jewelry, because 925 pure silver will change color when it meets fire. ?

Silver is dissolved in nitric acid to produce silver nitrate. Silver nitrate is a transparent crystal, which is photosensitive and easily soluble in water. Silver nitrate is the raw material for synthesizing many other silver compounds, and it can also be used as a preservative and a yellow additive in colored glass. Silver is not easy to react with sulfuric acid, so sulfuric acid is used to clean the copper oxide fire mark left by silver welding annealing in jewelry manufacturing. Silver easily reacts with sulfur and hydrogen sulfide (H2S) to produce black silver sulfide (Ag2S), which is commonly found on tarnished silver coins or other articles. Silver can react with oxygen at high temperature to produce brown-black silver oxide (it can also react at room temperature, but the speed is very slow). In the presence of potassium bromide (KBr), metallic silver will be eroded by strong oxidants such as potassium permanganate or potassium dichromate. These compounds are used in photography to bleach visible images.