Period 6 element 1783. Its important ores include wolframite and scheelite. The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all the non-alloyed metals and the second highest of all the elements after carbon. Also remarkable is its high density of 19.3 times that of water, comparable to that of uranium and gold, and much higher (about 1.7 times) than that of lead. Tungsten with minor amounts of impurities is often brittle and hard, making it difficult to work. However, very pure tungsten, though still hard, is more ductile, and can be cut
Melting-point apparatus range to be recorded. A Thiele tube is a glass instrument that is filled with oil that is heated by using an open flame. The sample is placed in the opening in a capillary tube alongside a mercury thermometer and allowed to be heated by the oil as it circulates through the Thiele tube. By using different oils, different temperature ranges can be reached and used to determine melting points. The Thiele tube may also be used to determine boiling points, by using a liquid sample instead of a solid sample. Melting-point apparatus A melting-point apparatus is a scientific instrument