Thursday, April 24, 2014

PRETTY LITTLE LIARS BOOM: Review 3x18 - Dead To Me

PRETTY LITTLE LIARS BOOM: Review 3x18 - Dead To Me: Parece que foi ontem que todos nós estávamos desesperados de ansiedade para que a fase 3B começasse logo. Pois a fase 3B começou e já está ...

Wednesday, April 23, 2014

Zinc Facts

Chemical & Physical Properties

 

Zinc
Atomic Number: 30
Symbol: Zn
Atomic Weight: 65.39
Discovery: known since prehistoric time
Electron Configuration: [Ar] 4s2 3d10
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, including brass, bronze, nickel silver, soft solder, Geman silver, spring brass, and aluminum solder. Zinc is used to make die castings for use in the electrical, automotive, and hardware industries. The alloy Prestal, consisting of 78% zinc and 22% aluminum, is nearly as strong as steel yet exhibits superplasticity. Zinc is used to galvanize other metals to prevent corrosion. Zinc oxide is used in paints, rubbers, cosmetics, plastics, inks, soap, batteries, pharmaceuticals, and many other products. Other zinc compounds are also widely used, such as zinc sulfide (luminous dials and fluorescent lights) and ZrZn2 (ferromagnetic materials). Zinc is an essential element for humans and other animal nutrition. Zinc-deficient animals require 50% more food to gain the same weight as animals with sufficient zinc. Zinc metal is not considered toxic, but if fresh zinc oxide is inhaled it can cause a disorder referred to as zinc chills or oxide shakes.

Is It Safe to Reboil Water?

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.

Grow a Cup-o-Crystals

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...

Darvaza Gas Crater - Extremely Cool Fire Tourist Attraction

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!

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...

Tuesday, April 22, 2014

This Day in Science History - April 22 - Rita Levi-Montalcini

April 22ndis the birthday of Rita Levi-Montalcini. She was awarded half the 1986 Nobel Prize in Medicine for the discovery of nerve growth factors. Upon graduation in 1936 with a medical degree, she was denied an academic or professional position in her native Italy under Mussolini's anti-Jewish laws. Instead, she set up a home laboratory in her bedroom and began researching nerve growth in chicken embryos. The paper she wrote on chick embryos earned her an invitation to a research position at Washington University in St. Louis, Missouri in 1947 where she stayed for the next 30 years. The Italian government recognized her by making her a member of the Italian Senate for life in 2001. She was a respected and active member of the Senate until her death in 2012 at the age of 103.

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 it. With that in mind, here's a look at some environment-related chemistry. I selected features that focus on cool features of the environment, like snowflakes and changing leaves, as well as issues, such as the greenhouse effect and fluoridation of drinking water.

Go Green for Earth Week - Make Your Own Shampoo

One of the biggest reasons to make your own shampoo is to avoid unwanted, potentially toxic chemicals. Another reason you might want to make your own shampoo is so you can customize the formulation for your hair's needs and your preference for fragrance (or lack of fragrance). Here's a recipe for a gentle vegetable-based shampoo. It's similar to my earlier shampoo recipe except this one uses potassium hydroxide instead of lye, which produces a shampoo that lathers better and rinses more easily. Mix the shampoo in a well-ventilated room or outdoors and be sure to read all of the safety precautions on the ingredients. Readers have recommended triethanolamine or diethanolamine in place of sodium hydroxide or potassium hydroxide. Choose the formulation that works best for you.
Shampoo Ingredients
  • 2 lb 10 oz olive oil
  • 1 lb 7 oz of solid-type vegetable shortening
  • 1 lb coconut oil
  • 14.4 oz potassium hydroxide
  • 2 pints water
  • 1-1/2 oz glycerine (glycerol)
  • 1/2 oz ethanol
  • 1-1/2 oz castor oil
  • essential oils (optional), such as peppermint, rosemary, lavender, for fragrance and therapeutic properties
Let's Make Shampoo!
  1. In a large pan, mix together the olive oil, shortening, and coconut oil.
  2. In a well-ventilated area, preferably wearing gloves and eye protection in case of accidents, mix the potassium hydroxide and water. Use a glass or enameled container. This is an exothermic reaction, so heat will be produced.

Why Do Clothes Wrinkle?

I think the only good thing about old permanent press fabrics is that they tended to disintegrate pretty quickly so you never had to wear them for long. They were itchy, smelly, and toxic, thanks to the presence of formaldehyde in the treatment that made them wrinkle-free (much like flame retardant clothing in those respects). Of course, modern wrinkle-free fabrics aren't nearly as heinous as their predecessors. Advances in polymer chemistry have led to significant improvements.

The key to both the cause of wrinkling and its solution lies in understanding chemical bonds. Wrinkles form when you break chemical bonds within fabric polymers and then reform them when the fabric is crumpled up. You can break bonds by heating fabric. Other polymers use hydrogen bonding, so getting those materials wet allows the hydrogen bonds in water to restructure the molecules. When you press clothes with a steam iron, you have both heat and water, so you can effectively remove wrinkles. Usually you can prevent them from forming in the first place, even with non-permanent press fabrics, by using a dryer with a cool down cycle and making sure the dryer runs long enough that your clothes are completely dry before the cycle stops.

420 and Marijuana

Today's date is 4-20, which means it's 420. What is 420? It's a sort of counterculture holiday which is associated with cannabis or marijuana. Wikipedia has a good overview of various 420 observances around the world. If you're interested in learning more about marijuana and its chemical properties and physiological effects, be sure to check out my Marijuana Facts page.

This Day in Science History - April 20 - Franz Achard

April 20th marks the passing of the man who first brought table sugar to the masses. Before Franz Achard came up with his refinement process, sugar was a luxury item available only to the wealthy. His process removed sucrose from common beets. This provided usable table sugar at such a low price where anyone could afford to keep sugar in their house.

Easy and Beautiful Glow Stick Lanterns

Glow sticks are pretty cool on their own, plus you can use them as the basis for other projects. For example, you can use the liquid inside glow sticks to make decorative lights or lanterns to use around your home or yard... wherever it is dark!

How to Make Glow in the Dark Ice

Glow in the dark ice is really easy to make. How did I do it? I opened up a bottle of tonic water, poured it into an ice cube tray, and stuck it in the freezer. Tonic water glows vivid bright blue under a black light. The glow is activated by other sources of ultraviolet light, such as fluorescent lights or sunlight, though the glow won't appear as bright in part because the room won't be as dark. If you want to duplicate the effect in the photo, you just need a black light somewhere in the room with the ice.

Glowing Ice Flavor Tips
Personally, I think tonic water tastes vile, so I have a couple of tips for improving the flavor of the ice cubes. The first tip is to dilute the tonic water. If you mix the tonic water with normal water your ice cubes will last longer (pure tonic water cubes melt fairly quickly) and won't taste as much like quinine (the ingredient responsible for the glow). Otherwise, you can cut it with lemonade or another sweet-sour drink that won't suffer from the bitter tang of the quinine. The second option is to put the ice into a drink where the flavor is desirable. The obvious choice would be to use the ice cubes in gin to make a gin and tonic. Non-alcoholic choices include fruit juice, Mountain Dew™, or Kool-Aid™. Don't worry about diminishing the glow from the ice. This photo is of tonic water ice and water.