Classification of microbes based on specific nutritional requirements. Heterotroph = use carbon sources (sugars, alcohols, carbs, fats, proteins) Autotroph = use inorganic carbon source (CO2) Chemotroph = use organic (glucose)/inorganic (reduced Fe2+) chemicals for energy.
You can color any metal containing iron, such as steel, with the oven heat of an ordinary kitchen range. Depending on the temperature setting, the steel changes color across a spectrum of shades ranging from pale yellow to dark blue. In addition, literally hundreds of chemicals will change the color of metal surfaces. Some of them are too toxic for amateurs to use. For example, cyanides, nitric acid, chromic acid, mercuric chloride, and lead acetate are hazardous chemicals only professionals should attempt to use.
Other ID Marks. 1) Tarnish. On a freshly broken surface, the color is bright metallic-white. Upon prolonged exposure, it tarnishes black, brown to gray, and dark yellow.2) Silver is the best conductor of electricity. Complex Tests. Dissolves in nitric acid and and sulfuric acid.ilver can be found pure, but is usually mixed with small amounts of gold, arsenic, and antimony. A natural alloy of gold and silver is known as Electrum, and is usually classified as a variety of Gold. Silver is a very resistant mineral. It does not dissolve in most solvent s, and won't react to oxygen or water.