Chemistry Archives - Page 12 of 22

27Feb 2017 by Vincent Summers No Comments

Vinyl Alcohol, Tautomerism, and Earth’s Atmosphere

[caption id="attachment_16229" align="alignright" width="480"] Sea spray salt aerosol[/caption] The simplest alcohols contain only carbon, oxygen, and hydrogen. Whereas water contains a hydrogen atom attached to a hydroxyl group, a simple alcohol consists of a chain of carbon and hydrogen atoms attached to a hydroxyl group. Vinyl alcohol is one of the simplest. In fact, it differs by just two hydrogen atoms from ordinary ethyl alcohol. Ethyl alcohol or ethanol is written, CH₃CH₂–OH. Vinyl alcohol or ethenol is CH₂=CH–OH. Though very similar, ethyl alcohol exhibits very ordinary, straightforward behavior, typical of an alcohol. Ethenol, however, due to its double bond, behaves differently. Tautomerization Vinyl alcohol rearranges slightly under ordinary conditions. It tautomerizes to the more stable species acetaldehyde. This variety of tautomerization is termed keto-enol tautomerism. The keto part refers to…

08Feb 2017 by Vincent Summers 2 Comments

Differences between Fluorescence, Phosphorescence, Incandescence

Chemistry, Physics

[caption id="attachment_16099" align="alignright" width="440"] Iridescence[/caption] Fluorescence, phosphorescence, incandescence. Though they sound similar, yet they are different. The differences need not be intimidating. First we’ll provide a brief definition of each; afterward, an explanation. We’ll add a few other similar sounding terms as well. These include iridescence, chemiluminescence, and radioluminescence. Fluorescence First, let us note that every one of these terms possesses some connection to light. Fluorescence is the rapid, even immediate emission of radiation, visible or invisible, proceeding the absorption of higher frequency (higher energy, shorter wavelength) radiation such as ultraviolet light. Certain rocks and minerals as well as marine biological specimens are fluorescent emitters. Phosphorescence [caption id="attachment_16101" align="alignright" width="360"] Phosphorescence[/caption] Similar to fluorescence, except the radiation takes place slowly over an extended time period. Heat and combustion are not…

30Jan 2017 by Vincent Summers No Comments

The Difference Between Alkanes, Alkenes, and Alkynes

Chemistry, Education

[caption id="attachment_16044" align="alignright" width="440"] An acetylene (ethyne) torch.[/caption] Alkanes, alkenes, and alkynes are made up of carbon and hydrogen. The carbon atoms in each exhibit a valency of four. Though these three hydrocarbon varieties are similar, there is a difference in bonding. We illustrate this with the simplest example: ethane vs. ethene vs. ethyne. Common and Scientific Names Common names are names given to many compounds, but they may mislead the uninitiated. For instance, the scientific names of alkenes contain the suffix –en(e) as part of their name. But acetylene is not an alkene. It is an alkyne. The scientific names of alkynes contains the suffix –yne. Acetylene is scientifically named ethyne. Yet, it nomenclature is not the only difference between alkanes, alkenes, and alkynes. Alkanes Alkanes are completely saturated…

30Jan 2017 by Vincent Summers 1 Comment

Tetra-Tert-Butyl Methane – The Acyclic Alkane That Seemingly Should Exist

Chemistry, Education

The smallest non-cyclic alkane that theoretically should exist, but to date has never successfully been prepared, is tetra-tert-butyl methane. The reason it is so elusive is crowding or steric hindrance. Introducing TTBM Tetra-tert-butyl methane is the common name of 3,3-ditert-butyl-2,2,4,4-tetramethylpentane. A glimpse at the structure reveals the overcrowding. Despite the overcrowding, according to energy calculations, the molecule (we’ll call it TTBM) should be capable of existence. Assembling the Model Even building the model from its component parts presented a measure of difficulty. The 17 carbon atoms (black spheres) and 36 hydrogen atoms (smaller white spheres) required some effort to assemble into TTBM. Still, it was accomplished with all the component atoms not touching one another. What is the problem or problems? [caption id="attachment_16028" align="alignleft" width="405"] Molecular Model TTBM[/caption] Synthesis While…

23Dec 2016 by Vincent Summers No Comments

Fly Ash for Concrete: Lowers Cost, Rids Waste and Aids the Environment

Chemistry, Technology

[caption id="attachment_15873" align="alignright" width="440"] Finding uses for waste products - Fly Ash[/caption] Fly ash for concrete? Most concrete is formulated from water, broken stone or gravel, sand, and cement—generally Portland cement. The formulation can include a small quantity of waste material. Fly ash is one such waste material. It offers three advantages. It reduces the need to dispose of some of earth’s abundant fly ash waste, it decreases cost, and decreases helps decrease damage to the environment. What is Fly Ash? Fly ash is the lightweight particulate carried along by flue gases produced from burning coal in boilers. It may be removed electrostatic precipitation. Although coal is mostly carbon, coal deposits are embedded in rock. Thus, inevitably, burning coal yields some silica (SiO2), alumina (Al₂2O3), and calcium oxide (CaO). Tragically,…

03Dec 2016 by Vincent Summers 4 Comments

Why Do My Fingernails Split Down the Middle?

Chemistry, Health

Even something as insignificant as fingernails can experience problems. For example, Nails Magazine discusses "longitudinal ridging", exacerbated by placing the hands in alcohol or water for long periods or by stress from typing or playing piano. Another difficulty is vertical splitting of the nails. An inconvenience, it is not overly serious. Sometimes fingernails split because the sufferer also has eczema or nail psoriasis. Why, hypothyroid can be a reason fingernails split! That’s How. Why? Imagine you have an 8-1/2” x 11” piece of paper used to print a check with a stub above the check. You must "tear along the dotted line". The perforation weakens the paper so it is easily tears along it. Similarly for some varieties of heavily grained wood. The wood splits along its grain, rather than…

07Nov 2016 by Vincent Summers 4 Comments

Aromatic Resonance – What It Is and What It Is Not

Chemistry

[caption id="attachment_19938" align="alignright" width="440"] Prominent resonance structures.[/caption] Sometimes a chemistry or physics concept is misunderstood even by the reader of above-average intelligence and education. Such is the case with the chemist’s use of the term aromatic resonance. There are a small number of recognized rules for aromatic behavior. These include: cyclic geometery planarity 4n + 2 contributing, de-localized, conjugated (π) double bonds An Example of What Aromatic Resonance Is Not The best and oldest known example is benzene, C₆H₆. Benzene is cyclic (one ring), planar (flat), and has 6 delocalized, conjugated double bonds. Frequently, the organic chemist simply renders benzene’s structure… There is a carbon atom at each vertex of the hexagonal ring. Attached to each carbon and pointing outward from it is one hydrogen atom. Now each carbon atom…

14Oct 2016 by Vincent Summers 2 Comments

Dangerous Chemistry of Jimson Weed – Watch Your Children!

Chemistry, Health

[caption id="attachment_15664" align="alignright" width="480"] Jimson Weed CCA Share Alike 3.0 by H. Zell[/caption] During the months of September and October, the reader may discover a disarmingly beautiful flowering weed. White to violet trumpets atop a green herbaceous plant, that after fertilization yields spiny seed pods, characterizes Jimson Weed (Datura stramonium) or Jamestown Weed, also called among other things, Locoweed, Hell’s Bells, and Devil’s Trumpet. All parts of the Jimson Weed contain toxic alkaloids in potentially fatal quantity. These include atropine, hyoscyamine, and scopamine. A dose used for its psychedelic effect is marginally less than a fatal dose. Hence, there have been many hospitalizations and deaths resulting from its use. Jimson Weed - Druggery [caption id="attachment_15667" align="alignleft" width="300"] Seed pod. Image by Nova CCA 3.0 Unported[/caption] Some smoke Jimson Weed thinking…

19Sep 2016 by Vincent Summers 2 Comments

What Is the Difference Between Table Salt and Other Salts?

Chemistry, Food

Nice try, but “s” is not the correct answer. There is a difference and there is no difference between them. Both are correct. There is a difference and there is not a difference between table salt and other salt(s). Difference Between Table Salt and Salts Table salt, chemical name sodium chloride, is written NaCl. Yes, we call it salt and we sprinkle it on our food. It enhances flavor to the palate. But to the chemist, it is merely one of thousands – millions of salts. So what is a salt to a chemist? It is one of two products (the other ordinarily water) of an acid-base reaction. Consider an example. An Example of a Salt Formation Calcium hydroxide plus sulfuric acid produces calcium sulfate plus water. Ca(OH)2 + H2SO4…

01Sep 2016 by Vincent Summers 1 Comment

Acids, Bases, Salts: Can An Oxide Be A Salt?

Chemistry, Education

[caption id="attachment_15469" align="alignright" width="440"] Aluminum chloride, hexahydrate. - Image Victor Claessen CC-SA 3.0.[/caption] Acids, bases, salts: Can an oxide be a salt? Let’s find out. Combine an acid and a base and you often get back a salt and water. This should be no surprise. It is high school chemistry. Assume we have a most simple acid, H-A. Too, we have a most simple base, B-OH. If we react the two, we expect the reaction mechanism to be written, H-A + B-OH → B-A + H2O H2O is, of course, water. B-A is the expected salt. Is An Oxide a Salt? Let us consider an example that deviates from the above simple concept—aluminum. Metals tend toward cationic (+) behavior. Non-metals act in opposite fashion, tending toward anionic (-) behavior. Aluminum…