16Apr 2019 by Vincent Summers No Comments

Ions are Stabilized by Spreading the Electric Charge

Chemistry, Physics
[caption id="attachment_23719" align="alignright" width="440"] This image depicts the spreading charge of a nitrate ion. Image by elpot[/caption] Ions are charged atoms or molecules. They may have a plus charge, a minus charge or – rarely – both. Examples of each are the positive sodium ion (Na+1), the negative bisulfate ion (HSO4-1) and the glycine zwitterion (or dipolar ion) (H3N+1‐CH2‐C(O)2-1). Spreading the electric charge will stabilize both positively and negatively-charged ions – but how does this work? Charge and Nature Even as “nature abhors a vacuum,” it likewise abhors a concentrated electric charge – lightning well illustrates this point. Although ordinary table salt exists in water solution as charged ions, those ions are not isolated as the above shorthand symbols would indicate. The ions are stable in water because the charge…
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13Feb 2018 by Vincent Summers No Comments

Is Cyclopropenethione Aromatic, As Is Its Oxygen Analog?

Chemistry, Logic
As small as it is, and even with a heteroatom in its make up, cyclopropenethione is aromatic, in the same way cyclopropenone is aromatic. Its aromaticity is not due to a theoretically electrically neutral structure, as in Figure 1, but to its "alternative" zwitterionic structure, shown in Figure 2. Aromatic Characteristics Hückel descriptors fall short of aromaticity if cyclopropenethione exhibited only the structure drawn in Figure 1. In addition to a closed and flat ring, aromaticity requires a 4n+2 number of π-electrons (pi), where n is usually a small integer. In the un-ionized form of Figure 1, each carbon atom has a π-electron, for a total of 3 electrons. This is because every double bond consists of one π-electron plus one σ-electron (sigma) per constituent atom. Widening Perspectives: Cyclopropenethione The…
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10Feb 2018 by Vincent Summers 9 Comments

Shampoo – Is It Soap, Is It Detergent, or What?

Chemistry, Health
Shampoos are hair-care products meant to clean hair while allowing it to remain manageable. Is shampoo soap, detergent, or what? Individual shampoo products may contain many different ingredients to impart additional characteristics, but largely mainstream shampoos consist of two combined surfactants. Sodium laureth sulfate or sodium lauryl sulfate is the main surfactant. Cocamidopropyl betaine is the secondary surfactant. We will consider these two ingredients in answering the title question. Sodium Lauryl Sulfate Sodium lauryl sulfate (also called sodium dodecyl sulfate) is an anionic surfactant. One online definition of a surfactant reads: "a substance that tends to reduce the surface tension of a liquid in which it is dissolved". For the purposes of our discussion, we identify sodium lauryl sulfate as a detergent, rather than a soap. Detergents do not fail…
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