08Dec 2013 by Vincent Summers 5 Comments

Which Weighs More – Wet Air or Dry Air?

Meteorology
[caption id="attachment_5407" align="alignright" width="440"] CCA Share Alike 3.0 Unported by Santhosh kumar[/caption] Air is mostly a mixture of gases and plus water vapor. The primary two gases are nitrogen and oxygen. We will state up front that the traces of other substances in air don’t affect the outcome of whether wet air or dry air is heavier. It all has to do with molecular weights. Nitrogen Nitrogen is a diatomic gas—chemical formula N₂. Its atomic weight is 14, therefore its molecular weight is 28. Nitrogen constitutes 78% of the atmosphere. [caption id="attachment_14807" align="alignright" width="280"] Barometer[/caption] Oxygen Oxygen is also a diatomic gas—chemical formula O₂. Its atomic weight is 16, therefore its molecular weight is 32. Oxygen constitutes 21% of the atmosphere. Dry Air Again, not considering the traces of other…
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27Dec 2012 by Vincent Summers 1 Comment

Forming Nitrogen Heterocycles from Aliphatic Amino Acids

Chemistry
How are nitrogen heterocycles formed from aromatic amines? Aliphatic hydrocarbons¹ take a number of forms. The simplest is written CH₃(CH₂)nCH₃, where n is a positive integer.²  Replace a hydrogen atom at one end of the chain with a carboxylic acid group (-COOH) and a hydrogen atom at the other end with an amino group (-NH₂), and you have a straight chain amino acid. For instance, choose n = 3. That gives the molecule HOOC-CH₂-CH₂-CH₂-CH₂-NH₂ Its name is 5-aminopentanoic acid or 5-aminovaleric acid. Cyclization Under the right conditions, this species can be cyclized to form an amine salt. The salt is then converted to a cyclic amide, a delta lactam. The lactam is next reduced to the amine piperidine. The overall process is illustrated in Fig. 1. Nitrogen Heterocycles A cyclic…
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