Saturday, January 18, 2014

Krypton Facts

Chemical & Physical Properties

 

Krypton
Atomic Number: 36
Symbol: Kr
Atomic Weight: 83.80
Discovery: Sir William Ramsey, M.W. Travers, 1898 (Great Britain)
Electron Configuration: [Ar] 4s2 3d10 4p6


Word Origin: Greek kryptos: hidden
Isotopes: There are 30 known isotopes of krypton ranging from Kr-69 to Kr-100. There are 6 stable isotopes: Kr-78 (0.35% abundance), Kr-80 (2.28% abundance), Kr-82 (11.58% abundance), Kr-83 (11.49% abundance), Kr-84 (57.00% abundance), and Kr-86 (17.30% abundance).
Element Classification: Inert Gas

Argon Facts

Chemical & Physical Properties of Argon

 

Argon
Atomic Number: 18
Symbol: Ar
Atomic Weight: 39.948
Discovery: Sir William Ramsay, Baron Rayleigh, 1894 (Scotland)
Electron Configuration: [Ne] 3s2 3p6






Word Origin: Greek: argos: inactive
Isotopes: There are 22 known isotopes of argon ranging from Ar-31 to Ar-51 and Ar-53. Natural argon is a mixture of three stable isotopes: Ar-36 (0.34%), Ar-38 (0.06%), Ar-40 (99.6%). Ar-39 (half-life = 269 yrs) is to determine the age of ice cores, ground water and igneous rocks.
Properties: Argon has a freezing point of -189.2°C, boiling point of -185.7°C, and density of 1.7837 g/l. Argon is considered to be a noble or inert gas and does not form true chemical compounds, although it does form a hydrate with a dissociation pressure of 105 atm at 0°C. Ion molecules of argon have been observed, including (ArKr)+, (ArXe)+, and (NeAr)+. Argon forms a clathrate with b hydroquinone, which is stable yet without true chemical bonds. Argon is two and a half times more soluble in water than nitrogen, with approximately the same solubility as oxygen. Argon's emission spectrum includes a characteristic set of red lines.

Chemical & Physical Properties of Neon

Neon
Atomic Number: 10
Symbol: Ne
Atomic Weight: 20.1797
Discovery: Sir William Ramsey, M.W. Travers 1898 (England)
Electron Configuration: [He]2s22p6

Word Origin: Greek neos: new
Isotopes: Natural neon is a mix of three isotopes. Five other unstable isotopes of neon are known.
Neon Properties: The melting point of neon is -248.67°C, boiling point is -246.048°C (1 atm), density of gas is 0.89990 g/l (1 atm, 0°C), density of liquid at b.p. is 1.207 g/cm3, and valence is 0. Neon is very inert, but it does form some compounds, such as with fluorine. The following ions are known: Ne+, (NeAr)+, (NeH)+, (HeNe)+. Neon is known to form an unstable hydrate. Neon plasma glows reddish orange. The discharge of neon is the most intense of the rare gases at ordinary currents and voltages.

Chemical & Physical Properties of Helium

Helium
Helium Atomic Number: 2
Helium Symbol: He
Helium Atomic Weight: 4.002602(2)
Helium Discovery: Janssen, 1868, some sources say Sir William Ramsey, Nils Langet, P.T. Cleve 1895
Helium Electron Configuration: 1s2
Word Origin: Greek: helios, sun. Helium was first detected as a new spectral line during a solar eclipse.
Isotopes: 7 isotopes of helium are known.
Properties: Helium is a very light, inert, colorless gas. Helium has the lowest melting point of any element. It is the only liquid that cannot be solidified by lowering the temperature. It remains liquid down to absolute zero at ordinary pressures, but can be solidified by increasing the pressure. The specific heat of helium gas is unusually high. The density of helium vapor at the normal boiling point is also very high, with the vapor expanding greatly when heated to room temperature. Although helium normally has a valence of zero, it has a weak tendency to combine with certain other elements.

This Day in Science History - January 18 - Edward Frankland

January 18th is Edward Frankland's birthday. Frankland was an English chemist who pioneered the idea of valency. He theorized the an element could combine with a limited selection of other elements and established the field of structural chemistry.

Together with Joseph Lockyer, Frankland discovered the only element to be discovered outside of Earth before it was discovered terrestrially. Both men were investigating the spectrum given off by the sun when they found a series of lines that did not correspond to any known elements. They named their discovery "helium" after the Sun, or Helios. Their discovery coincided with French astronomer Pierre Janssen solar eclipse discovery of helium.

Helium was only found in the spectra of stars and nebulae but never on Earth. It would take another 30 years before helium was detected in an ore of uranium by Swedish chemists Per Teodor Cleve and Nils Langlet. Find out what else occurred on this day in science history.

Make Disappearing Ink

Once upon a time on a high school field trip, my class visited a magic shop, where we got some disappearing ink. We had great fun spritzing each other with the dark blue ink, which became invisble after a few seconds of exposure in the air. The teacher who was our chaperone wasn't quite as amused as we were when her silk blouse was 'stained' with the ink. The color disappeared, but a visible spot remained from the liquid on a dry-clean-only fabric. Therefore, these instructions for disappearing ink are presented to you with the advice that you don't spray the ink onto anything that can't survive washing. Otherwise, disappearing ink is easy to make and can be used to demonstrate acid-base indicators.

Dieting May Cause Positive DUI Breathalyzer Test

Here's a bit of chemistry you may want to know if you're ever pulled over and given a breath test: dieting can cause you to test positive for a DUI breathalyzer. According to the National Substance Abuse Index, many breathalyzers measure methyl groups, which are a product of alcohol metabolism, rather than the presence of ethyl alcohol itself. This means that any chemical exposure or metabolic process that produces methyl groups may produce a false positive breathalyzer result. High protein, low carbohydrate diets, including the Atkins diet, causes your body to produce ketones or acetone, which the test reads as a possible metabolite from drinking alcohol. Other causes of false positive DUI breathalyzer tests include absorption of chemicals from pumping gas, inhaling glue fumes, handling glue or medical conditions including hyperglycemia.
In-car ignition interlock devices may test for alcohol, but non-specifically, meaning any alcohol will register a positive result. Strict dieting may produce isopropanol, an alcohol which would make you unable to start your car.

This Day in Science History - January 17 - Pluto

January 17th marks the passing of two people, William Pickering and Clyde Tombaugh, who were important to the discovery of the dwarf planet, Pluto.

William Pickering was an American astronomer who believed there was a planet outside the orbit of Neptune that caused the unusual shape of the orbit of Neptune and Uranus. He was instrumental in the establishment of Lowell observatory in Flagstaff, Arizona with Percival Lowell to search for this "Planet X". Powell spent the rest of his life searching, even photographing Pluto on film twice without recognizing the planet.

Clyde Tombaugh joined the staff at Lowell Observatory and was given the task of taking systematic photographs of portions of the night sky on two nights one week apart. He would load the images in a device called a blink comparator that rapidly switches the two photographs. This allowed Tombaugh to detect slight differences between the photographs which would suggest movement. He found a change from his late January plates and confirmed the discovery with another photograph. He had discovered a new planet and the formal announcement was made on March 13, 1930.

The name "Pluto" was chosen from a selection of submitted possible names. It originally came from an 11-year-old girl from Oxford, England named Venetia Burney.

What Are the Ingredients in Rubbing Alcohol?

Question: What Are the Ingredients in Rubbing Alcohol?
Answer: One of the types of alcohol you can buy over the counter is rubbing alcohol, which is used for disinfection and may be applied to the skin to produce a cooling effect. Do you know the chemical composition of rubbing alcohol? It is a mixture of denatured alcohol, water and agents added to make the alcohol unpalatable to drink and sometimes colorants. There are two common types of rubbing alcohol.

Isopropyl Rubbing Alcohol

Most rubbing alcohol is made from isopropyl alcohol or isopropanol in water. It is common to find isopropyl rubbing alcohol at concentrations from 68% alcohol in water up to 99% alcohol in water. The 70% rubbing alcohol is highly effective as a disinfectant. Additives make this alcohol bitter-tasting, to try to prevent people from drinking it. Isopropyl alcohol is toxic, in part because the body metabolizes it into acetone. Drinking this alcohol can cause headache, dizziness, nausea, vomiting, central nervous system depression, organ damage and potentially coma or death.

Vanishing Valentine Chemistry Demonstration

Here's a fun chemistry demonstration that's perfect for Valentine's Day or to illustrate an oxidation-reduction reaction. The Vanishing Valentine involves shaking a solution, causing it to turn pink. If the pink Valentine solution is left undisturbed, it will become colorless. The color change cycle can be repeated several times. It is caused by the oxidation and reduction of resazurin. an indicator that is pink or colorless depending on its oxidation state.

Vanishing Valentine Materials

  • 100 ml of a 0.133 M dextrose solution (C6H12O6)
  • 100 ml of a 1.0 M sodium hydroxide solution (NaOH)
  • 1 ml of a 0.1% resazurin solution
  • a 250-ml or 500 ml Erlenmeyer flask or separatory funnel (resembles a heart)
  • stopper for the flask
  • dropper or pipette

Prepare the Solutions

Dextrose Solution: Dissolve 2.4 g of dextrose in distilled or deionized water to make 100 ml of solution. Sodium Hydroxide Solution: Prepare the 1.0 M sodium hydroxide solution by dissolving 4.0 g of sodium hydroxide in enough distilled or deionized water to make 100 ml of solution. Add the sodium hydroxide a little at time, stirring constantly. Heat is evolved from this reaction.
Resazurin Solution: Dissolve 0.1 g of resazurin in distilled or deionized water to make 100 ml of solution. The shelf life of resazurin solution is 6-12 months. This solution should be a deep blue color.

Perform the Vanishing Valentine Demonstration

  1. Pour 100 ml of dextrose solution and 100 ml of sodium hydroxide solution into the Erlenmeyer flask or separatory funnel.
  2. Add 8 drops of resazurin indicator solution to the flask or funnel.
  3. Stopper the solution and swirl the flask to mix the contents. Initially the solution will be blue.
  4. Allow the solution to sit undisturbed. Once the resazurin is fully reduced the solution will become clear or colorless. This may take up to 10 minutes.
  5. Swirl or shake the solution to turn it a pink Valentine color.
  6. The clear-pink cycle may be repeated by allowing the solution to sit and then shaking it again. Once prepared, the solution lasts approximately an hour (depending on temperature and available oxygen in the flask). The pink color will become less vivid over time.

Vanishing Valentine Chemical Reactions

Dextrose irreversibly reduces resazurin to resorufin. The red resorufin molecule is further reduced (reversibly) to colorless dihydroresorufin. Dihydroresorufin (clear) may be oxidized back to resorufin (pink) by swirling or shaking the flask to introduce oxygen from the air into the solution.

Vanishing Valentine Demo Safety

Wear appropriate chemistry lab safety gear when performing this demonstration, such as a lab apron, gloves and safety goggles. While the resazurin and dextrose solutions are not hazardous, sodium hydroxide solutions are caustic and could produce a chemical burn if spilled on the skin or splashed into the eyes.

Wednesday, January 15, 2014

How to make hard candy


How to Make Rock Candy

Although it may look complicated to make, rock candy is simply made of crystallized sugar. In this video, learn how to make this classic treat

Atoms and Atomic Theory - Study Guide

Chemistry is the study of matter and the interactions between different types of matter and energy. The fundamental building block of matter is the atom. An atom consists of three main parts: protons, neutrons, and electrons. Protons have a positive electrical charge. Neutrons have no electrical charge. Electrons have a negative electrical charge. Protons and neutrons are found together in what is called the nucleus of the atom. Electrons circle around nucleus.
Chemical reactions involve interactions between the electrons of one atom and the electrons of another atom. Atoms which have different amounts of electrons and protons have a positive or negative electrical charge and are called ions. When atoms bond together, they can make larger building blocks of matter called molecules.

Atomic Abundance Example Chemistry Problem

The element boron consists of two isotopes, 105B and 115B. Their masses, based on the carbon scale, are 10.01 and 11.01, respectively. The abundance of 105B is 20.0%.
What is the atomic abundance of and the abundance of 115B?
Solution
The percentages of multiple isotopes must add up to 100%.
Since boron only has two isotopes, the abundance of one must be 100.0 - the abundance of the other.
abundance of 115B = 100.0 - abundance of 105B
abundance of 115B = 100.0 - 20.0
abundance of 115B = 80.0
Answer
The atomic abundance of 115B is 80%

This Day in Science History - January 15 - Artturi Ilmari Virtanen

January 15th is Artturi Ilmari Virtanen's birthday. Virtanen was a Finnish biochemist who invented the AIV (his initials) fodder technique to prevent spoilage in stored green silage. Storing green plant fodder during long winters was always difficult since by the end of winter, it would ferment and be rendered inedible and possibly result in starvation. Virtanen noticed the process of fermentation would cease when a particular acidity was reached. He prepared a solution of dilute hydrochloric or sulfuric acid and added it to the stored fodder. The fodder remained fresh and did not affect its nutritive value.

This discovery greatly changed the way agricultural fodder is stored. It also earned Virtanen the 1945 Nobel Prize in Chemistry.

1997 - Kenneth Vivian Thimann died.

Thimann was an English-American plant physiologist who isolated the plant growth hormone auxin. Auxin promotes cell elongation, formation of roots, and growth of buds in plants. Thimann's discovery led to the development of synthetic auxin to create products to functions ranging from root enhancers to weed killers.

The Ultimate Chemistry Kit That Still Uses Real Chemicals

Thames and Kosmos produces several science kits, including multiple chemistry sets. The Chem C3000 is their ultimate chemistry kit. Chemistry education and labs have moved toward computer simulations and 'safe' chemicals, so it's actually quite hard to find a kit that offers the types of hands-on experimentation that set the standard for chemistry labs in the past. The Chem 3000 is one of the few chemistry kits on the market today that contains chemicals and equipment necessary to perform over 350 high school / advanced chemistry experiments. This is the most popular chemistry kit for home school chemistry and self-teaching.

Description

This is the ultimate chemistry kit! Thames & Kosmos Chem C3000 kit contains everything in their Chem C1000 and Chem C2000 kits, plus more chemicals and equipment. You'll be able to perform over 350 chemistry experiments.

The kit comes in a box containing two styrofoam packing trays. The company reserves the right to make technical changes in the kit, so there isn't much point in listing the exact contents of the box I received, but I will say it included a 192-page paperback color lab manual, safety glasses, stickers for labeling chemicals, test tubes, a test tuber holder and test tube brush, a funnel, graduated beakers, pipettes, stoppers, an alcohol burner, a tripod stand, electrodes, brown bottles for storing light-sensitive chemicals, rubber hoses, glass tubing, filter paper, an evaporating dish, an Erlenmeyer flask, a plastic syringe, litmus powder, an assortment of other lab necessities, and numerous containers of chemicals. As you might expect, there's nothing particularly dangerous with respect to waste disposal (e.g., no mercury, carbon tetrachloride, etc.), but it's a serious set, intended for hands-on, old school chemistry experimentation.

The experiments introduce the investigator to proper use of chemistry lab equipment and cover general chemistry and introductory organic essentials.

Best Chemistry Set - Thames and Kosmos Kits

Thames and Kosmos makes several serious chemistry kits that include glassware, chemicals, and detailed workbooks that explain how to perform experiments. These kits are perfect for anyone looking for the full chemistry lab experience, including students seeking to satisfy home school requirements. The Chem C1000 and Chem C2000 kits offer numerous experiments at economical prices. The Chem C3000 kit is an exceptional complete set that essentially sets you up with a home chemistry lab and chemicals to perform hundreds of experiments. Although Thames and Kosmos makes high-end advanced sets, the company also makes introductory kits for kids.

List of Top Chemistry Kits

Chemistry kits are a fun way to introduce kids to hands-on chemistry, plus they are a must-have if you're learning chemistry from home. I've tried many kits over the years. Some were duds, while others offered hours of engagement, reliable results, and clear instructions. Here's a short list of my favorite sets, grouped by experience level and topic


Metal Trivia Quiz

You know what metals are. You have iron in your blood, might wear a gold or silver ring on your finger, and eat using stainless steel utensils. Yet, how good are you at metal trivia? What interesting facts about metals do you know?... Take the quiz

Tuesday, January 14, 2014

This Day in Science History - January 14 - Cato Guldberg

January 14th marks the passing of Cato Guldberg. Cato and Peter Waage were Norwegian chemists who discovered the chemistry law of mass action. The law of mass action relates the rate of a reaction to the concentration of the reactants. They had an interesting journey to get their work recognized and is a lesson in getting published in the 'right' scientific journals. They initially published their findings in a Norwegian scientific journal and consequently, gained very little recognition for their research. They republished their work in a French journal which did not attract any more attention. Their work remained obscure until German chemist, Wilhelm Ostwald published an article that mentioned the law and proved their results with experiments of his own. Dutch chemist Jacobus van't Hoff derived his kinetics equations in 1888 and received credit for the discovery, they republished again in a German journal and finally got the recognition for their work.

2005 - Huygens proble lands on Titan.

 The European Space Agency's Huygens probe touched down on the surface of Saturn's moon, Titan. It was part of the Cassini-Huygens spacecraft mission to Saturn. The probe detached from the main spacecraft and landed two weeks later. The probe sent back images and data for another 90 minutes before battery power was drained. The probe was named for Dutch astronomer Christiaan Huygens who discovered the rings of Saturn and the moon, Titan.

10 Common Naturally Radioactive Foods

Technically, all food is slightly radioactive. This is because all food and other organic molecules contain carbon, which naturally exists as a mixture of isotopes, including radioactive carbon-14. That's the basis for carbon dating, used to identify the age of fossils. However, some foods emit much more radiation than others. Here's a look at 10 naturally radioactive foods and how much radiation you get from them.

1. Brazil Nuts


If there was an award for "Most Radioactive Food," it would go to Brazil nuts. Brazil nuts contain high levels of two radioactive elements: radium and potassium. Potassium is good for you, used in many biochemical reactions, and one of the reasons why the human body is itself slightly radioactive. Radium occurs in the ground where the trees grow and is absorbed by the plant's root system. Brazil nuts emit over 6,600 pCi/kg of radiation. Most of that radiation passes harmlessly through the body, plus the high levels of healthful selenium and other minerals make these nuts healthy to eat in moderation.

2. Lima Beans

Lima beans are high in radioactive potassium-40 and also radon-226. Expect to get 2 to 5 pCi/kg from radon-226 and 4,640 pCi/kg from potassium-40. You don't any benefit from the radon, but the potassium is a 'good' mineral in lima beans. Lima beans are also a good source of (non-radioactive) iron.

3. Bananas

 Bananas are sufficiently radioactive that they can set off radiation alarms at ports and airports. They offer 1 pCi/kg from radon-226 and 3,520 pCi/kg from potassium-40. The high potassium content is part of why bananas are so nutritious. You do absorb the radiation, but it's not harmful.

10 Radioactive Foods

Some of the foods you eat are naturally radioactive. Sometimes the radiation comes from isotopes that a plant absorbs as it's growing, while other foods are radioactive because they contain high levels of elements that exist as a mixture of isotopes. Pictured here is a common food that emits radiation.

 Question: What Is Radioactivity? What is Radiation?
 
 Unstable atomic nuclei will spontaneously decompose to form nuclei with a higher stability. The decomposition process is called radioactivity. The energy and particles which are released during the decomposition process are called radiation. When unstable nuclei decompose in nature, the process is referred to as natural radioactivity. When the unstable nuclei are prepared in the laboratory, the decomposition is called induced radioactivity.
Answer: There are three major types of natural radioactivity:
  1. Alpha Radiation Alpha radiation consists of a stream of positively charged particles, called alpha particles, which have an atomic mass of 4 and a charge of +2 (a helium nucleus). When an alpha particle is ejected from a nucleus, the mass number of the nucleus decreases by four units and the atomic number decreases by two units. For example:
    23892U → 42He + 23490Th
    The helium nucleus is the alpha particle.
  2. Beta RadiationBeta radiation is a stream of electrons, called beta particles. When a beta particle is ejected, a neutron in the nucleus is converted to a proton, so the mass number of the nucleus is unchanged, but the atomic number increases by one unit. For example:
    234900-1e + 23491Pa
    The electron is the beta particle.
  3. Gamma RadiationGamma rays are high-energy photons with a very short wavelength (0.0005 to 0.1 nm). The emission of gamma radiation results from an energy change within the atomic nucleus. Gamma emission changes neither the atomic number nor the atomic mass. Alpha and beta emission are often accompanied by gamma emission, as an excited nucleus drops to a lower and more stable energy state.
Alpha, beta, and gamma radiation also accompany induced radioactivity. Radioactive isotopes are prepared in the lab using bombardment reactions to convert a stable nucleus into one which is radioactive. Positron (particle with the same mass as an electron, but a charge of +1 instead of -1) emission isn't observed in natural radioactivity, but it is a common mode of decay in induced radioactivity. Bombardment reactions can be used to produce very heavy elements, including many which don't occur in nature.

How To Calculate Standard Deviation

One of the most common calculations you'll be expected to perform on data is standard deviation. It is so important that most calculators have a button for it! However, you should be able to do this calculation by hand, plus you need to know which standard deviation formula to apply. That's right! There is more than one.
Apply the population standard deviationformula when you are analyzing a complete set of data. This may be data from all the members of a class or all the trials of an experiment. Apply the sample standard deviation formula when you are analyzing a sample or set of samples from a larger population.
Note that the sample standard deviation formula contains a correction factor, called Bessel's correction, that expresses increased uncertainty in how reliable your data is. Why would you do this? The correction factor helps form a more realistic prediction of what you could expect from future testing. It is helpful when you can't get data from every single sample of a set.
Here are some examples of how to perform both standard deviation calculations, using the same set of data so you can see how Bessel's correction affects the final value.

What Is Standard Deviation?

Standard deviation is the average or mean of all the averages for multiple sets of data. Scientists and statisticians use the standard deviation to determine how closely sets of data are to the mean of all the sets. Standard deviation is an easy calculation to perform. Many calculators have a standard deviation function, but you can perform the calculation by hand, and should understand how it is done.

Monday, January 13, 2014

Understanding Global Warming from First Principles

Michael de Podesta studied Physics at Sussex University, receiving his B.Sc. in 1981 and was awarded a D.Phil. in 1985. After postdoctoral work at Bristol University he was appointed a lecturer at the University of London in 1987 and joined NPL in 2000. Since then he has specialised in temperature measurements of all kinds and has recently completed the most accurate measurement of temperature in history. Michael is a chartered physicist, a member of the Institute of Physics and in 2009 he was awarded an MBE for Services to Science.

 
The webinar begins by asking the question “Why is the Earth’s surface the temperature it is?”. The answer to this question is not contentious but is often not fully appreciated. This understanding then forms the basis of an analysis of why scientists are concerned that human emissions of carbon dioxide are causing Global Warming.

How To Learn Chemistry Fast

Do you need to learn chemistry fast? Here is how you do it!

Plan To Learn Chemistry Fast

The first step is to determine exactly how long you have to learn chemistry. You'll need a lot more discipline to learn chemistry in a day compared with a week or a month. Also, keep in mind you won't have great retention if you cram chemistry in a day or a week. Ideally you want a month or longer to master any course. If you do end up cramming chemistry, expect to review the material if you need to apply it to a higher level chemistry course or remember it for a test further down the road.

A Word About Chemistry Lab

If you can do labwork, that's fantastic, because the hands-on learning will reinforce the concepts. However, labs take time, so most likely you'll miss this segment. Keep in mind labs are required for some situations. For example, you have to document labwork for AP Chemistry and many online courses. If you are doing labs, check how long they take to perform before getting starting. Some labs take less than an hour start-to-finish, while others might take hours, days or weeks. Pick short exercises, whenever possible. Supplement book learning with videos, which are readily available online.

Gather Your Materials

You can use any chemistry textbook, but some are better than others for fast learning. I would use an AP Chemistry book or Kaplan Study Guide or similar book. These are high quality, time-tested reviews that cover everything. Avoid dumbed-down books because you'll get the illusion that you learned chemistry, but won't master the topic.

What Does pH Stand For?

pH is a measure of hydrogen ion concentration or [H+] in an aqueous solution. It is a useful gauge of the acidity of a solution. Yet, do you know why we use the symbol "pH" or what it stands for?

Have you ever wondered what pH stands for or where the term originated? Here is the answer to the question and a look at the history of the pH scale.

Question: What Does pH Stand For?
 
 

Answer: pH is the negative log of hydrogen ion concentration in a water-based solution. The term "pH" was first described by Danish biochemist Søren Peter Lauritz Sørensen in 1909. pH is an abbreviation for "power of hydrogen" where "p" is short for the German word for power, potenz and H is the element symbol for hydrogen. The H is capitalized because it is standard to capitalize element symbols. The abbreviation also works in French, with pouvoir hydrogen translating as "the power of hydrogen".

Logarithmic Scale

The pH scale is a logarithmic scale that usually runs from 1 to 14. Each whole pH value below 7 (the pH of pure water) is ten times more acidic than the higher value and each whole pH value above 7 is ten times less acidic than the one below it. For example, a pH of 3 is ten times more acidic than a pH of 4 and 100 times (10 times 10) more acidic than a pH value of 5. So, a strong acid may have a pH of 1-2, while a strong base may have a pH of 13-14. A pH near 7 is considered to be neutral.

This Day in Science History - January 13 - Paul Niggli

January 13th marks the passing of Paul Niggli. Niggli was a Swiss mineralogist who was a pioneer of x-ray crystallography. He developed the mathematical system of space groups that defined 230 different atom arrangements based on x-ray diffraction patterns. X-ray crystallography works by shining x-ray radiation through a crystal structure and detecting the interference pattern generated by the gaps between individual atoms. This information can tell you the position of atoms in a crystal, the width of atomic bonds, and even the size of the atoms themselves. All this information can give detailed help in determining the structure of a molecule. All that is really needed is a pure sample that can be crystallized.

1927 - Sydney Brenner was born.

Brenner is a South African biologist who shares the 2002 Nobel Prize in Medicine with H. Robert Horvitz and John Sulston for their discoveries of how genes regulate organ development and cell death. His research centered on the use of the nematode Caenorhabditis elegans and the identification of which genes control programmed cell death.

1900 - Peter Waage died.

Cato Maximilian Guldberg (1836 - 1902) and Peter Waage (1833 - 1900)
Wikimedia Commons
Waage was a Norwegian chemist who, together with Cato Guldberg, discovered the Law of Mass Action. This law relates the rate of a chemical reaction is proportional to the amount of active mass, or concentration, of the reactants. This law became the basis for determining rate constants of chemical reactions.

1864 - Wilhelm Wien was born.

Wilhelm Wien (1864 - 1928) 
Wien was a German physicist who was awarded the 1911 Nobel Prize in Physics for his laws involving the radiation of heat. He determined a blackbody curve at any temperature is determined from the blackbody curve at any other temperature by displacing the wavelength of the emission energy. This is known as Wien's displacement law.

Turn Water into Liquid Gold

Mix two clear solutions, wait, and watch the liquid turn to gold! This is a simple alchemy project or chemistry demonstration, based on early attempts to make gold from base metals.

 

 

Liquid Gold Materials

Solution A
  • 1 gram sodium arsenite
  • 50 ml water
  • 5.5 ml glacial acetic acid
Prepare Solution A by stirring the sodium arsenite into the water. Mix the glacial acetic acid into this solution. Solution B
  • 10 grams sodium thiosulfate (photographer hypo)
  • 50 ml water
Prepare Solution B by stirring the sodium thiosulfate into the water.

Let's Make Liquid Gold!

Pour one solution into the other. The clear solution will turn gold after about 30 seconds. For dramatic effect, keep track of the time and command the solution to turn into gold. You can even use a magic word, if you like.

The Chemistry Behind How It Works

There is a delayed reaction between the acid and the sodium thiosulfate to release hydrogen sulfide gas. The hydrogen sulfide reacts in turn with sodium arsenite to precipitate tiny crystals of golden arsenious sulfide, which is also known as arsenic trisulfide (As2S3) or orpiment. Both Western and Chinese alchemists experimented with orpiment to try to make gold. Although the mineral can be made to appear metallic under certain conditions, the compound does not undergo any reaction which changes either the arsenic or the sulfur into gold. It's a striking demonstration though!

Turn Water Into Gold - Alchemy Project

One of the quests of the ancient alchemists (and possibly modern ones as well) was to transmute a base material into gold. While it's possible to turn lead into gold using a particle accelerator, alchemists tend to seek chemical reactions that might produce gold. One reaction they explored appeared to turn water into gold. You can try this too, as an interesting experiment or as a memorable chemistry demonstration.

How to Get Lithium from a Battery

You can obtain pure lithium from a lithium battery. It's an adult-only project and even then, you need to use safety precautions, but it's simple and easy.

 

 

Safety Precautions

Lithium reacts with moisture and may spontaneously ignite. Don't allow it to come in contact with your skin. Also, cutting into a battery often causes a short circuit, which may produce a fire. While this is not unexpected or problematic, it does mean you need to perform this procedure on a fire-safe surface such as concrete, preferably outdoors. Eye and skin protection is a must.

Materials

You want a new battery for this project since the lithium can be extracted as a relatively uncorroded metal foil. If you use a used battery you'll get a product that might be better for making colored fire, but it will be impure and fragile.
  • New Lithium Battery (e.g., AA or 9V lithium battery)
  • Safety Glasses or Goggles
  • Gloves
  • Insulated Wirecutters and Pliers

Procedure

Basically you cut the top off the battery to expose the roll of lithium metal foil inside. The "trick" is to do this without shorting out the battery. While you don't want a fire, be prepared for one. Simply drop the battery and let it burn out. This should not take long and usually won't damage much of the lithium metal in the battery. Once the fire is out, proceed.
  1. You're wearing protective gear and know not-to-panic if you see fire, right? Okay then, use the cutters to carefully remove the top from the battery. This is when you're most likely to accidentally cause a short. Try to cut the tough outer rim of the casing without hitting the central core.
  2. Quickly cut any connections and remove any rings or disks from the top of the battery. If the battery starts to get hot, you likely have a short. Cut away anything suspicious to address the issue.Cut and peel back the casing to expose the metal core, which is the lithium. Use pliers to extract the lithium. Try not to puncture the central plastic container, as this can lead to a short and fire. It's sort of like playing that Operation game except if you touch something you shouldn't, you'll heat up the metal and potentially see fire.
  3. Pull away the plastic tape or wrap and unroll the metal. The shiny metal is aluminum foil, which you may remove and discard. Black powdery material is electrolyte, which you can wrap in plastic and discard in a fire-safe container. Remove any additional plastic. You should be left with sheets of lithium metal, which will oxidize as you watch from silver to brown.
  4. Either use the lithium right away or store it right away. It degrades quickly in air, especially humid air. You can use the lithium for projects (for example, it burns bright white as a metal while its salts impart a red color to flames or fireworks) or store the lithium under liquid paraffin oil.

Caffeine and Other Stimulants That Cause Psychosis

While you may know Adderall and other amphetamines can cause psychosis (in addition to other effects), were you aware other stimulants can cause psychotic behavior, including caffeine? This is called stimulant psychosis and is characterized by:
  • delusions
  • hallucinations
  • disordered thinking
  • catatonia (extreme cases)
Physical symptoms are those of stimulant overdose, which you can get without suffering stimulant psychosis:
  • nausea
  • diarrhea
  • hypertension (high blood pressure)
  • rapid breathing
  • hyperthermia (elevated temperature)
  • sleep deprivation
  • tremor
Drugs that are known to cause stimulant psychosis include:
  • amphetamines
  • methylphenidate (Ritalin)
  • cocaine
  • caffeine
The effect typically occurs at high doses or from chronic use. Often it is temporary, although sometimes recovery is incomplete. In the case of caffeine, psychosis may be related to lack of B-vitamins, nervous system exhaustion, or a pre-existing mental condition. It's somewhat controversial because the drug by itself may not be sufficient to cause the condition. That's probably good news for readers presently finishing up a pot of coffee or their third energy drink.

This Day in Science History - January 11 - First Use of Insulin

On January 11, 1922 insulin was used for the first time on a human patient. Leonard Thompson, a 14-year-old diabetic at Toronto General Hospital received an injection of Dr. Banting and Best's recently purified insulin. They had previously tested their hormone on dogs with positive results. Leonard's diabetes seemed to recede but he developed an allergic reaction. This reaction was later traced to an impurity in their sample and a more purified sample was used two weeks later.

Leonard survived his previous death sentence of diabetes for another 13 years using insulin until he died from pneumonia at age 27. Dr. Best would later earn the 1923 Nobel Prize in Medicine for this achievement and diabetics everywhere were given a chance at a normal life.

Why Is Chemistry Important?

If you've ever been asked to explain why chemistry is important, you may have found it challenging to explain what must seem so obvious to you! If you teach chemistry or are a parent, you're bound to get asked this question. If you're taking chemistry, answering why chemistry is important is a common assignment. Here's my answer and a chance for you to answer the question, too:  

Answer: Chemistry has a reputation for being a complicated and boring science, but for the most part, that reputation is undeserved. Fireworks and explosions are based on chemistry, so it's definitely not a boring science. If you take classes in chemistry, you'll apply math and logic, which can make studying chemistry a challenge if you are weak in those areas. However, anyone can understand the basics of how things work... and that's the study of chemistry. In a nutshell, the importance of chemistry is that it explains the world around you. Chemistry Explains... * Cooking Chemistry explains how food changes as you cook it, how it rots, how to preserve food, how your body uses the food you eat, and how ingredients interact to make food. * Cleaning Part of the importance of chemistry is it explains how cleaning works. You use chemistry to help decide what cleaner is best for dishes, laundry, yourself, and your home. You use chemistry when you use bleaches and disinfectants and even ordinary soap and water. How do they work? That's chemistry! * Medicine You need to understand basic chemistry so you can understand how vitamins, supplements, and drugs can help or harm you. Part of the importance of chemistry lies in developing and testing new medical treatments and medicines. * Environmental Issues Chemistry is at the heart of environmental issues. What makes one chemical a nutrient and another chemical a pollutant? How can you clean up the environment? What processes can produce the things you need without harming the environment? We're all chemists. We use chemicals every day and perform chemical reactions without thinking much about them. Chemistry is important because everything you do is chemistry! Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything. Importance of Taking Chemistry Everyone can and should understand basic chemistry, but it may be important to take a course in chemistry or even make a career out of it. It's important to understand chemistry if you are studying any of the sciences because all of the sciences involve matter and the interactions between types of matter. Students wanting to become doctors, nurses, physicists, nutritionists, geologists, pharmacists, and (of course) chemists all study chemistry. You might want to make a career of chemistry because chemistry-related jobs are plentiful and high-paying. The importance of chemistry won't be diminished over time, so it will remain a promising career path.