Glossary of Chemical Terms - P

P

peptide

A small polymer of amino acids, formed by the condensation copolymerization of several amino acids.

period

The horizontal rows in the periodic table.

pH

A measure of the amount of hydrogen ions in a solution, equal to the negative of the base-10 logarithm of the hydrogen ion concentration.

pharmacology

The science of drugs; the properties of drugs related to their therapeutic effects.

phentermine

Amphetamine-like component of fen-phen that increases metabolism by raising the body's levels of dopamine and norepinephrine.

photon

A particle of electromagnetic radiation having zero mass.

photosynthesis

Process in which water and carbon dioxide are combined in the presence of sunlight to produce glucose and oxygen.This is the process used by green plants to create their food.

phytoplankton

Algae, microscopic single-celled plants that float in the surface waters of the sea, lakes and rivers. In the ocean they constitute the bottom of the marine food chain. They have been called 'the pasture of the sea.' Like plants on land, they use sunlight to convert carbondioxide and water into sugars and oxygen in the process of photosynthesis.

phytoremediation

Using plants to clear toxic metals from the environment by chelation.

plasma

A gas-like phase of matter that contains charged particles.

polarizability

Indication of the ease of distortion of an electron cloud around at atom.Large atoms (like iodine) have many electrons, and their location may easily shift, producing regions of partial positive and negative charge.The larger the atom, the greater the polarizability, or the more easily an electron cloud may be distorted.

pollutant

A substance that contaminates an environment.

polycarbonate

A polymer in which the repeating unit is an organic carbonate [-R-O-C(O)-O-]_n.

polymer

Molecules which are composed of linked repeating units (called monomers) are referred to as polymers. Polymers are the basis for many plastics and synthetic fibers such as Teflon and polyester.

porosity

The ratio of the size of a material's pores to the volume of the material's mass.

precipitate

A solid formed in a chemical reaction.

precision

The agreement of repeated measurements with each other.

precursor

In metabolism, a chemical substance from which another chemical substance is formed

pressure

The force per unit area.

protein

A biological polymer formed by condensation reactions among a set of 20 different amino acids.

proton

A positively charged subatomic particle found in the nucleus.

protonated

Having acquired an additional proton (H⁺).

Glossary created by David Shaw (Madison Area Technical College) for The Chemistry Place.

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