A

 Any material or substance capable to accept into its inner structure another substance.

 One of a large class of chemical substances whose water solutions have one or more of the following properties:

• sour taste;
• ability to make litmus dye turn to red;
• ability to react with and dissolve certain metals to form salts; and
• ability to react with bases or alkalis to form salts.

All acids contain hydrogen. In water, ionization (splitting of the molecule) occurs. Acids are referred to as strong or weak according to the concentration of hydrogen ion that results from ionization.

 Any substance, inorganic or organic, natural or synthetic, that is capable of bonding other substances together by surface attachment.

 A class of hydroxyl containing organic compounds. They have a generic formula C_nH_2n+1OH (for saturated hydrocarbons), where OH is a hydroxyl group. There are also alcohols for unsaturated hydrocarbons. Alcohols in general are colourless liquids with a wide range of boiling points. Alcohols from methyl to butyl are mobile liquids. Those from C₅ to C₁₁ are oily liquids; above C₁₂ they are usually solids. The most toxic members of the class are methyl alcohol and allyl alcohol.

 These are calcium, barium, strontium and radium (group II A of the Periodic Table).

 Radioactive substance (material) or article, which contains radioactive material that spontaneously emits alpha particles (helium nucleus). Alpha particle has atomic mass 4 and the positive charge 2.

 Any of a group of organic compounds which have the structure (-C-N=N-C-). Electrons involved in such kinds of bonds have complicated orbits, and are extremely sensitive to additional input of external energy, which makes them capable of breaking the existing bonds. The breaking of the bonds affects the whole molecule which undergoes spontaneous decomposition.

 One of the major groups of organic compounds characterized by straight-chain arrangements of the constituent carbon atoms.

 Descriptive of an inorganic compound that does not contain water either adsorbed on its surface or combined as water of crystallization.

 A major group of unsaturated cyclic hydrocarbons containing one or more rings. Example: benzene group (1 ring), naphthalene group (2 rings) and anthracene group (3 rings).

 Organic compounds which have in their molecules aromatic radicals bonded with groups with the structure (-SO₂-NH-NH₂). Electrons involved in such kinds of bonds have notably complicated orbits, and are extremely sensitive to additional input of external energy, which makes them capable of breaking the existing bonds. The breaking of the bonds affects the whole molecule, which undergoes spontaneous decomposition.

 Any of a group of compounds having the characteristic formula R (N₃)_x. R may be almost any metal atom, a hydrogen atom, a halogen atom, the ammonium radical, certain inorganic complexes and organic radical. The azide group has a chain structure N=N=N. Electrons involved in such kinds of bonds have complicated orbits, and are extremely sensitive to additional input of external energy, which makes them capable of breaking the existing bonds. The breaking of the bonds affects the whole molecule which undergoes spontaneous decomposition. All the heavy metal azides, hydrogen azide and most the light metal azides are explosives. Many of the organic azides are explosives