Friday, March 20, 2020
Beryllium Facts - Periodic Table of the Elements
Beryllium Facts - Periodic Table of the Elements Beryllium Atomic Number: 4 Symbol: Be Atomic Weight: 9.012182(3)Reference: IUPAC 2009 Discovery: 1798, Louis-Nicholas Vauquelin (France) Electron Configuration: [He]2s2 Other Names: Glucinium or Glucinum Word Origin: Greek: beryllos, beryl; Greek: glykys, sweet (note that beryllium is toxic) Properties: Beryllium has a melting point of 1287/-5à °C, boiling point of 2970à °C, specific gravity of 1.848 (20à °C), and valence of 2. The metal is steel-gray in color, very light, with one of the highest melting points of the light metals. Its modulus of elasticity is a third higher than that of steel. Beryllium has high thermal conductivity, is nonmagnetic, and resists attack by concentrated nitric acid. Beryllium resists oxidation in air at ordinary temperatures. The metal has a high permeability to x-radiation. When bombarded by alpha particles, it yields neutrons in the ratio of approximately 30 million neutrons per million alpha particles. Beryllium and its compounds are toxic and should not be tasted to verify the metals sweetness. Uses: Precious forms of beryl include aquamarine, morganite, and emerald. Beryllium is used as an alloying agent in producing beryllium copper, which is used for springs, electrical contacts, nonsparking tools, and spot-welding electrodes. It is used in many structural components of the space shuttle and other aerospace craft. Beryllium foil is used in x-ray lithography for making integrated circuits. It is used as a reflector or moderator in nuclear reactions. Beryllium is used in gyroscopes and computer parts. The oxide has a very high melting point and is used in ceramics and nuclear applications. Sources: Beryllium is found in approximately 30 mineral species, including beryl (3BeO Al2O3à ·6SiO2), bertrandite (4BeOà ·2SiO2à ·H2O), chrysoberyl, and phenacite. The metal may be prepared by reducing beryllium fluoride with magnesium metal. Element Classification: Alkaline-earth Metal Isotopes: Beryllium has ten known isotopes, ranging from Be-5 to Be-14. Be-9 is the only stable isotope.Density (g/cc): 1.848 Specific Gravity (at 20 à °C): 1.848 Appearance: hard, brittle, steel-gray metal Melting Point: 1287 à °C Boiling Point: 2471 à °C Atomic Radius (pm): 112 Atomic Volume (cc/mol): 5.0 Covalent Radius (pm): 90 Ionic Radius: 35 (2e) Specific Heat (20à °C J/g mol): 1.824 Fusion Heat (kJ/mol): 12.21 Evaporation Heat (kJ/mol): 309 Debye Temperature (K): 1000.00 Pauling Negativity Number: 1.57 First Ionizing Energy (kJ/mol): 898.8 Oxidation States: 2 Lattice Structure:Hexagonal Lattice Constant (Ãâ¦): 2.290 Lattice C/A Ratio: 1.567 CAS Registry Number: 7440-41-7 Beryllium Trivia Beryllium was originally named glyceynum due to the sweet taste of beryllium salts. (glykis is Greek for sweet). The name was changed to beryllium to avoid confusion with other sweet tasting elements and a genus of plants called glucine. Beryllium became the official name of the element in 1957.James Chadwick bombarded beryllium with alpha particles and observed a subatomic particle with no electrical charge, leading to the discovery of the neutron.Pure beryllium was isolated in 1828 by two different chemists independently: German chemist Friederich Wà ¶hler and French chemist Antoine Bussy.Wà ¶hler was the chemist who first proposed the name beryllium for the new element. Source Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Langes Handbook of Chemistry (1952), CRC Handbook of Chemistry Physics (18th Ed.), CRC Handbook of Chemistry and Physics (89th Ed.)
Tuesday, March 3, 2020
Turn Water into Wine or Blood with Chemistry
Turn Water into Wine or Blood with Chemistry This popular chemistry demonstration is often called turning water into wine or water into blood. Its really a simple example of a pH indicator. Phenolphthalein is added to water, which is then poured into a second glass containing a base. If the pH of the resulting solution is right, you can make the water turn from clear to red to clear again, as long as you like. Heres How Sprinkle sodium carbonate to coat the bottom of a drinking glass.Fill a second glass halfway full of water. Add ~10 drops phenolphthalein indicator solution to the water. The glasses can be prepared in advance.To change water into wine or blood, pour the water with indicator into the glass that contains the sodium carbonate. Stir the contents to mix the sodium carbonate, and the water will change from clear to red.If you like, you can use a straw to blow air into the red liquid to change it back to clear.The principle is the same as for the disappearing ink formula. Phenolphthalein is an acid-base indicator. Tips Phenolphthalein and sodium carbonate can be ordered freely from any scientific supplier. Most grade school and high school science labs have these chemicals, though you can order them yourself.Dont drink the water/wine/blood. It isnt particularly toxic, but it isnt good for you either. The liquid can be poured down the drain when the demonstration is complete.For a normal drinking glass, the ratio used to get the reversible color change reaction is 5 parts sodium carbonate per 10 drops of a phenolphthalein stock solution. What You Need Phenolphthalein pH indicatorSodium carbonateWater2 glassesStirring rodStraw or pipette
Subscribe to:
Posts (Atom)