Chemistry

An explosion is nothing more than the rapid release of energy. This is most commonly due to the rapid combustion of a material, although nuclear explosions do not involve combustion. The combustion of any hydrocarbon or other carbon-containing substance ALWAYS produces carbon dioxide. This might include explosion due to a natural gas or gasoline.

It is possible, however, to explode substances that do not contain carbon, such as pure hydrogen (the very famous Hindenburg disaster in 1937 is a classic example of a very big hydrogen gas explosion. An explosion of hydrogen produces only water vapor (H2O), NOT carbon dioxide (CO2).

Also, nuclear explosions (both fusion and fission) themselves do not produce carbon dioxide, although they may cause surrounding objects to incinerate, which would release carbon dioxide.

The octet rule is a simple chemical rule of thumb that states that atoms tend to combine in such a way that they each have eight electrons in their valence shells, giving them the same electronic configuration as a noble gas. This 8-electron configuration is especially stable because with 8 valence electrons, the s- and p-orbitals are completely filled (with 2 in the s-orbital, and 6 in the p-orbitals). Having completely filled orbitals provides increased stability due to something called "exchange energy."

The rule is applicable to the main-group elements, especially carbon, nitrogen, oxygen, and the halogens, but also the metals in the first two columns of the periodic table (but not to the transition metals in the middle of the periodic table). Note that the elements hydrogen (H) and helium (He) do not follow the octet rule, but rather the "duet" rule (2 electrons) because they do not have any p-orbital electrons.

In simple terms, molecules or ions tend to be most stable when the outermost electron shells of their constituent atoms contain eight electrons. The rule is commonly used in drawing Lewis dot structures.

One major reason I can think of, that has not been addressed yet, is the periodicity of the elements. You can line the elements up into neat functional groups--alkali metals, transition elements, halogens and so on. This you could not do with compounds, even if you had a separate table for hydrocarbons, one for elastomers, and one for dyestuffs... Compounds also find wide use as smaller blocks of larger compounds. We call these precursors. Take toluene. It is a very toxic compound, but if you compound it into toluene diisocyanate, then compound that into polyurethane, it becomes safe enough that you can build it into replacement hip joints. Chemists do keep books of compounds, but a table on a big sheet of paper the size of...oh, the entire side of a Wal-Mart store might be big enough? It could never happen.

The HBr molecule is linear (obviously, since it contains only two atoms). The dipole moment is a vector, parallel to the bond, pointing toward the partially positively charged atom, which is, in this case, the hydrogen. The magnitude of the dipole moment is the difference in the partial electrical charges on each atom times the spatial separation of the atoms in the bond. In a molecule with more than two atoms (more than one bond), the dipole moment of each bond must be added vectorially and the resultant vector will determine the dipole moment of the molecule. For instance, carbon dioxide has two carbon-oxygen double bonds of high polarity, but because the molecule is linear, and the individual dipoles oppose each other, the carbon dioxide molecule has no net dipole moment.

A substituted hydrocarbon is a hydrocarbon with one or more of the hydrogen is substituted with another element, (often a halogen such as chlorine or bromine) or another group of atoms such as -OH. Examples: -

a simple hydrocarbon is methane CH4. Substitute chlorine for hydrogen to get

CH3Cl Methyl Chloride is used for cleaning. Sub. Again to get

CH2Cl2 Methylene Chloride is used as paint stripper. Sub again to get

CHCl3 Chloroform is an ancient anesthetic. Sub again to get

CCl4 Carbon Tetrachloride is used in cleaning and fire extinguishers.

Substitute a single -OH group into -

CH4 to get CH3OH methanol or into C2H6 to get C2H5OH ethanol

The above examples all begin with unbranched non-cyclic hydrocarbons, but any hydrocarbon is a suitable target. A well-known instance is a double substitution of chlorine at opposite ends of a benzene ring to form paradichlorbenzene, commonly found hanging in toilet bowls. C6H6 becomes C6H4Cl2

A dipole moment is defined as a measure of the molecular polarity of a compound; the magnitude of the partial charges on the ends of a molecule times the distance between them (in meters).

In order for there to be a dipole moment, the element must have molecular polarity, which results from molecules with a net imbalance of charge (often a result of differences in electro negativity). If the molecule has more than two atoms, both shape and bond polarity determines the molecular polarity.

In general, look for a difference in electro negativity of the elements of a molecule which results in polarity and thus a possible dipole moment. Note that molecular shape influence polarity so molecules with the same elements but a different shape (and vice versa) will not have the same dipole moment.