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Chemical & Physical Properties   Zinc Atomic Number: 30 Symbol: Zn Atomic Weight: 65.39 Discovery: known since prehistoric time Electron Configuration: [Ar] 4s 2 3d 10 Word Origin: German zinke : of obscure origin, probably German for tine. Zinc metal crystals are sharp and pointed. It could also be attributed to the German word 'zin' meaning tin. Isotopes: There are 30 known isotopes of zinc ranging from Zn-54 to Zn-83 . Zinc has five stable isotopes: Zn-64 (48.63%), Zn-66 (27.90%), Zn-67 (4.10%), Zn-68 (18.75%) and Zn-70 (0.6%). Properties: Zinc has a melting point of 419.58°C, boiling point of 907°C, specific gravity of 7.133 (25°C), with a valence of 2. Zinc is a lustous blue-white metal. It is brittle at low temperatures, but becomes malleable at 100-150°C. It is a fair electrical conductor. Zinc burns in air at high red heat, evolving white clouds of zinc oxide. Uses: Zinc is used to form numerous alloys, inclu...

You may have heard that is is unhealthy to reboil water or even to boil it away when cooking. Unless your water is exceedingly pure, reboiling water drives off the gases dissolved in the water and evaporates away some of the water, concentrating minerals and contaminants. There are two safety concerns with reboiling water. The first is that reboiling water increases the chance you'll get burned. With the gas bubbles removed, reboiling water can cause it to superheat and suddenly splash out when disturbed. The other safety issue concerns the chemical composition of reboiled water.

From my list of quick crystal projects, here's a favorite. This one takes a minute to set up, yielding a mass of needle-like crystals after about three hours in your refrigerator. All you need is a cup or small, narrow bowl, epsom salts, and water. Grow Crystals in a Cup...

Have you heard of the Darvaza Gas Crater or The Burning Gate to Hell? It is a massive burning crater that resulted from a natural gas accident that occurred in either the 1950s or else 1971, depending on who tells the tale. The drilling rig fell into a natural cavern, which was set alight. It still burns today. I don't see myself planning a vacation to the Karakum desert in Turkmenistan anytime soon, but if I went there, I would be sure to check this out. Photos of the Darvaza Crater are stunning. There are also some YouTube videos of the so-called "Door to Hell" out there. Pretty cool, don't you think

chemistry learn center : Happy Earth Day! : Happy Earth Day! The purpose of the day is to inspire appreciation for the earth's environment and awareness of issues that threaten...