Chemistry Archives - Page 6 of 22

20Apr 2019 by Vincent Summers No Comments

Diamondoids: Adamantane, Diamantane and Triamantane Practical Uses?

Carbon readily bonds to itself. This unusual characteristic allows the existence of a whole host of hydrocarbons, some of which assume amazing geometric shapes. Cyclopropane (C3H6) looks like an equilateral triangle. Cubane (C8H4) is a cube. In recent years, Bucky balls, graphene sheets and nanotubes have become household topics. Diamondoids Diamondoids are compounds of hydrogen and carbon consisting of cage-like structures that resemble the diamond lattice. Carbon-carbon bond lengths are 1.54 Ångstrom units (1 Å = 10-8 centimeters) in length both for diamond and for diamantane. But the structures themselves are difficult to compare. Please take some time to ponder the unit cell image for diamond and the chemical structures of the first three diamondoids of the series, adamantane (C10H16), diamantane (C14H20), and triamantane (C18H24). Diamondoid to Diamond? Diamond is…

19Apr 2019 by Vincent Summers 1 Comment

Degrees of Oxidation Using Methane as an Example

Chemistry

One tool of the organic chemist is that of oxidation. There are abundant reagents, which vary in reactivity and strength, to choose from to create this reaction. A plethora of techniques guarantee specificity. All are important to the synthetic organic chemist and to industry. What is a reagent? It is a chemical that is of interest because it can react with the substance chemists wish to modify and study. Oxidizers are one kind of reagent. Consider the progressive oxidation of methane (CH₄) from its lowest to its highest oxidation state. The progression of the oxidation of methane products is written simply, CH₄ → CH₃OH → HCHO → HC(O)OH → HC(O)OOH [→ CO₂ + H₂O ] Their names (left to right) are methane, methyl alcohol, formaldehyde, formic acid, performic acid, and…

19Apr 2019 by Vincent Summers No Comments

Cutting Edge Technology: Gold Nanoparticles for Research

Chemistry, Medicine

[caption id="attachment_24005" align="alignright" width="480"] Using a nanoparticle-based sensing strategy for determining protein levels in blood. Image by Vincent Rotello, University of Massachusetts[/caption] There is spellbinding beauty in “yellow, yellow” gold. But gold is not always yellow. If individual gold atoms are clumped together in small quantities – agglomerated – they assume various colors depending upon the physical properties of the agglomerates. If all the particles are of about the same size and shape, the color and other physical properties, when duplicated, are exactly reproduced. Interestingly, aggregates can be grown with a specific geometry. They can even be grown into the particularly useful form – nanorods. The assortment of colors that can be produced ranges from red to purple to blue. But there is a problem. If gold nanoparticles grown with…

19Apr 2019 by Vincent Summers 1 Comment

Hydrochlorothiazide HCTZ: The Time-Tested, Inexpensive B.P. Medication

Chemistry, Medicine

Many think that “New is better.” In technology, such thinking often proves true. But is it always the case? No. Consider pharmacology. New drugs promise improved health, a better quality of life. Yet negative side effects, some not having had sufficient time to surface, may discourage a medication’s use, perhaps even warranting its removal from pharmacy shelves. In the United States, one of the most common health issues is hypertension – high blood pressure. So it’s no surprise many medicines have been formulated to fight this condition. Although many new drugs are now available, hydrochlorothiazide (HCTZ) remains a “first choice” for the treatment of hypertension.1 Why so? Few medicines have such a generally excellent track record. HCTZ (or for short, HCT) has few side-effects.2 Hydrochlorothiazide is inexpensive; perhaps it is…

19Apr 2019 by Vincent Summers 1 Comment

Muonium: An Atom Similar to Hydrogen, Only No Protons!

Chemistry, Physics

[caption id="attachment_23970" align="alignright" width="480"] No proton![/caption] You heard correctly! From cosmic ray bombardments and particle accelerator experiments comes “muonium,” an other-worldly form of atom that, to a degree, resembles hydrogen. This atom is fascinating research scientists, along with another oddball, positronium. An Exotic Element… Sort Of There are some 90 naturally-occurring elements on Earth. There are more than a dozen other artificial elements, as well. Muonium is artificial, but not in the usual sense of the term. All of the more than one-hundred elements found in the periodic table consist of atoms made up of electrons traveling in orbitals about respective nuclei containing one or more protons and neutrons. Though muonium does have an electron orbiting a nucleus, it possesses no proton or neutron. Instead, it’s nucleus consists of an…

18Apr 2019 by Vincent Summers 1 Comment

Introduction to Chemistry Subscripts and Superscripts

Chemistry, Education

Subscript and superscript can make all the difference when it comes to chemical formulas. Molecules, compounds, and other chemical structures include more than one atom. Sometimes, there are multiples of one particular atom. For instance, anhydrous aluminum chloride features one atom of aluminum joined to or combined with three atoms of chlorine. Its chemical formula reflects this: AlCl3. But – simply knowing how to use a number in this instance is not enough. It is essential to know the proper use of subscripts and superscripts. Subscripts in Chemistry Notice the number 3 is written as a subscript, or a number that is smaller than the other text, and below the normal text line, in the formula for anhydrous aluminum chloride above. The concept of a multiplicity of atoms is conveyed…

18Apr 2019 by Vincent Summers 3 Comments

Where Does Crude Oil Come From? Biotic or Abiotic Processes?

Chemistry, Education

Crude oil is used in the production of gasoline, diesel fuel, and other important substances, including plastics. The crude oil comes from the ground beneath our feet. But the question arises, how did it get there? Where Does Crude Oil Come From? There are two basic theories for the origin of crude oil: biotic and abiotic. The biotic theory predominates. It attributes oil’s formation to the decay of animal and plant matter. The less widely accepted – even controversial – abiotic theory denies the involvement of living organisms in the production of crude oil. These two theories are finding most of their adherents in two camps – the Western camp (biotic) and the Russian-Ukrainian camp (abiotic) – although there are western scientists in the R-U camp. This division is especially…

18Apr 2019 by Vincent Summers 1 Comment

Cyclosilicates: Beautiful Gemstones of Technological Interest

Chemistry, Technology

[caption id="attachment_23902" align="alignright" width="440"] Aquamarine cyclosilicate. Image by Vassil[/caption] Straight-chain silicates are common in nature. The anionic or negative portion of the silicates consists of silicon and oxygen, sometimes in conjunction with metals Thus there are aluminosilicates, magnesium silicates, and ferrosilicates. Sodium silicate, one of the most common examples, is simply, Na2SiO3. In its anhydrous form, sodium silicate adopts a tetrahedrally-linked polymeric form. Most silicates are not cyclic. Yet, the most beautiful silicates in the world – the most beautiful gemstones – are cyclosilicates. Interestingly, it is the technological beauty of these silicates that has been turning heads. It may be that the most beautiful thing about cyclosilicates is their hole. What Are Cyclosilicates? Cyclosilicates have the same tetrahedral linkage as other silicates, but in their case, the chain ends…

16Apr 2019 by Vincent Summers 2 Comments

Which are Stronger? Covalent or Ionic Bonds?

Chemistry, Physics

Almost all the atoms found in nature, left alone to themselves, are stable structures. If they always remained such, there would be no need of chemists. Fortunately, when in close contact, atoms can react in a number of ways. Often they link to each other in various combinations through bonding, forming molecules called compounds. Such interaction requires explanation, and so provides employment to humans educated in this field: The field called chemistry. Chemical Bonds: Ionic and Covalent There are a variety of ways atoms bond to one another. Some bonds are weaker, and some are stronger. Two of the strongest forms of chemical bond are the ionic and the covalent bonds. Chemical bonds form between two atoms, each with its own electron environment. If each of the two atoms shares…

16Apr 2019 by Vincent Summers No Comments

The Improbable Making and Chemistry of Chocolate

Chemistry, Food

[caption id="attachment_23742" align="alignright" width="480"] Cacao pods contain the makings of chocolate, but the contents must first go through a fermentation and drying process. Image by Medicaster.[/caption] Some years ago, some made the claim that genuine chocolate isn’t ‘good for you’. They made the claim that artificial chocolate made from carob beans is superior. Curiously, so-called dog chocolate was already made from carob... Thank goodness, science now concedes that chocolate is not all that bad; most of us can eat and enjoy at least some chocolate. And now that we know it’s OK to eat chocolate – and it may even be good for us – did you ever wonder: How do we make cocoa from cacao, and what is the chemistry behind this treat? Chocolate Chemistry: The Cacao Bean The…