30Aug 2020 by Vincent Summers No Comments

Hydrofluoric Acid: A Weak Acid – Yet It Dissolves Glass?

Chemistry
On the far right side of the Periodic Table of the Elements is listed the halogens, which include fluorine, chlorine, bromine, iodine, and astatine. In order of ascending atomic weight we have: fluorine and chlorine gases, bromine liquid, and iodine and astatine solids. Each exhibits a –1 valence. Each attaches to a single atom of hydrogen to form an anhydrous acid. Most of these acids are considered very strong with the exception of hydrofluoric acid. It is comparably a relatively weak acid. This is the case, even though hydrofluoric is the only acid stored in polyethylene bottles because it dissolves glass. Since it can eat its way through glass, how can hydrofluoric acid be considered a weak acid? Hydrofluoric Acid Attacks Glass While hydrofluoric acid is usually written HF, for…
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29Aug 2020 by Vincent Summers No Comments

Structure of Hydrazoic Acid and Its Azide Derivatives

Chemistry
When we think of nitrogen and hydrogen, we are likely to think first of ammonia, NH3. But what of hydrazoic acid? Hydrazoic acid is HN3. It looks to be the opposite of ammonia. What is the chemical structure of hydrazoic acid and its azide derivatives? And why are they of importance to us? Valence Consideration When we think of hydrogen, we think of a +1 valence, though at times it is assigned a –1 valence. Similarly, nitrogen ordinarily assumes either a +3 or a +5 valence. Both ammonia and hydrazoic acid exhibit a +3 valence for nitrogen. All of this is well and good, but what is the structure of ammonia? of hydrazoic acid and the azides? In both instances, we may be surprised that what we imagine may not…
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26Aug 2020 by Vincent Summers No Comments

[12]Annulene and Two Simple Derivatives – Aromaticity?

Chemistry
Complex chemicals possess names almost equally complex. Occasionally, a simpler nomenclature can be employed. For basic aromatic compounds, composed of a ring of alternating single and double bonded carbon atoms in a ring, the name [n]annulene has been is commonly used. Examples, including [12]annulene are given below. Aromaticity We won't go into the theory behind aromaticity. What we will do is lay out the basic factors that students use to determine if a compound is aromatic. 1. The ring is composed of conjugated single and double bonds (...−C=C−C=...). 2. The molecule is relatively flat. 3. The number of available π-electrons equals 4n + 2 (a Hückel number), where n is generally a small positive integer.¹ 4. Crowding does not severely limit or prevent aromaticity. 5. Ring size affects aromaticity, but…
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20Aug 2020 by Vincent Summers No Comments

What’s the Difference Between Wax and Paraffin?

Chemistry, Language
[caption id="attachment_28810" align="alignright" width="480"] Not paraffin... Bees wax candles.[/caption]What's the Difference Between Wax and Paraffin? Waxes and paraffin would seem to refer to the same thing, and perhaps to some extent, the words are used interchangeably. In fact, paraffin is sometimes called paraffin wax or petroleum wax. Nevertheless, technically, they are different, and the difference should interest us. Let's begin with what a wax is. Waxes Waxes are esters1 of a long-chain alcohol2 (12 to 32 carbon atoms) with a fatty acid. One example of a long-chain alcohol is lauryl alcohol (CH3(CH2)11OH). But what is a fatty acid? A fatty acid is (typically) a carboxylic acid that has a long carbon chain3. One example is palmitic acid (CH3(CH2)14COOH). Palmitic acid is a saturated4 fatty acid. Some fatty acids are unsaturated.…
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25Jul 2020 by Vincent Summers No Comments

Hemoglobin A1C: Reason for the Test and the Science Behind It

Chemistry, Health
[caption id="attachment_28695" align="alignright" width="480"] Red blood cells or erythrocytes.[/caption]The term HbA1C and its more common abbreviation A1C, is a familiar term to the diabetic or pre-diabetic patient. A1C refers to blood hemoglobin that has bonded to sugar molecules. It is easy to detect, and since it is stable over time, the A1C blood test is an excellent indicator of "blood sugar" level. Article Contents We here present artwork and a brief text, coupled with a most helpful Khan Academy video, so that, hopefully, the pre-diabetic or diabetic patient, who has a measure of technical background, can understand what the A1C test is all about. Hemoglobin Image Our second image illustrates hemoglobin's 3-D branch structure using red for its two alpha (α) chains and blue for its two beta (β) chains.…
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09May 2020 by Vincent Summers No Comments

Differences Between Citric and Ascorbic Acid (Vitamin C)

Chemistry
Two familiar acids, found in citrus fruit, are citric acid and ascorbic acid (Vitamin C). But what are these acids and how are they different? First, consider the structure of these two food acids. Examine the Image The two acids look different, yet somehow they look similar. Each has a ring, or what almost passes as a ring, and each contains an abundance of oxygen atoms (O). There are three carboxylic acid groups –C=O(OH) are found in the citric acid molecule. On the other hand, ascorbic acid contains no carboxylic acid groups. Yet it, too, is acidic, about as acidic as vinegar. Citric acid with its carboxylic acid groups is the more acidic acid and so is more sour to the taste. But why is ascorbic acid acidic if it…
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02Sep 2019 by Vincent Summers 1 Comment

The Chemical Structure of the Anti-Fungal Iodopropynyl Butylcarbamate

Chemistry, Health
Ever purchased wipes or some other product that was labeled hypoallergenic? Why did the label say that? Hypoallergenic is defined as: relatively unlikely to cause an allergic reaction. So all the ingredients in such a product must have a well-established safety record. Even if a few individuals experience difficulty, it would be mild, perhaps superficial. There is a compound that, despite being hypoallergenic, fights mold successfully. Its name? Iodopropynyl butylcarbamate. The achieved objective requires only a very slight amount of IPBC. Effective at minimal concentrations and water-soluble, IPBC is a cost-effective anti-fungal preservative. A Closer Look at IPBC Notice the chemical structure of iodopropynyl butylcarbamate in the illustration. The portion of the molecule encircled by green is the carbamate portion of the molecule. It is a derivative of carbamic acid…
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25Aug 2019 by Vincent Summers No Comments

Odor Chemistry: Lady Beetle Vs. Marmorated Stink Bug

Chemistry, Nature
It was the ol' one-two. First we were attacked by Asian Lady Bird Beetles, Harmonia axyridis, then the brown marmorated stink bug, Halyomorpha halys. The Lady Bird Beetles were detected first in Louisiana in 1988. Close on its heels, the Stink bugs were detected in Pennsylvania in 1996. Both exude horrible odors when provoked or crushed, though the constituent chemicals are entirely different. Stink Bug Chemistry The stench of the Stink Bug is actually rather simple, as far as stenches go. Two organic compounds, each a "first cousin" of the other, are the culprits: trans-2-octenal and trans-2-decenal (see image). These two compounds are classified as both aldehydes (-CHO) and alkenes (-C=C-). Let's first examine how they are named. Notice both compounds have a straight chain or backbone of carbon atoms…
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17Aug 2019 by Vincent Summers No Comments

Woodward cis-Hydroxylation Reaction

Chemistry, Medicine
Silver acetate, in combination with iodine, forms the initial reactant package for the Woodward reaction. This reaction, carried to completion, selectively converts an alkene into a cis-diol. The prefix cis- refers to the addition of two atoms (or groups of atoms) to the same side of a molecular double bond. Trans-, when used, refers to addition across the double bond – of one atom or group to one side, one to the other side. The Mechanism The mechanism is illustrated in the image (below) up to the point of hydrolysis. The product of that hydrolysis is pictured in the introductory image. We see, first, the iodine splits, the I atom adding to the double bond. In the next part of the reaction, the silver atom attaches to the iodine, and…
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15Aug 2019 by Vincent Summers 2 Comments

How Does Bleach Bleach? What Removes the Color?

Chemistry
When doing the laundry, we ask, what temperature should the water be, how much detergent should I use, will I need fabric softener, will I need bleach? If I use bleach, should I use chlorine bleach or should I use oxygen bleach? Kinds of Bleach There are two kinds of bleach, based on needed strength and fabric sensitivity. Chlorine bleach, historically the older and stronger variety, is based on sodium or calcium hypochlorite, NaOCl or CaOCl. One name brand of laundry bleach is Clorox®. It contains 5.25% NaOCl. How does chlorine bleach remove color? In order to understand that, we need first to ask, what is the chemistry behind the colors used in fabrics? Color in Fabrics When we think of colors applied to fabrics, the chemist usually thinks of…
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