Page 47 - Encyclopedia of Chemical Compounds 3 Vols

Words to Know

OXIDIZE To combine a substance with oxygen, or to remove
hydrogen from a molecule using oxygen, or to remove
electrons from a molecule.
•
P

PARTICULATE MATTER Tiny particles of pollutants sus-
pended in the air.

PETROCHEMICALS Chemical compounds that form in rocks,
such as petroleum and coal.

PH (POTENTIAL HYDROGEN) The acidity or alkalinity of a
substance based on its concentration of hydrogen ions.

PHOSPHATE A compound that is a salt of phosphoric acid,
which consists of phosphorus, oxygen, sometimes hydro-
gen, and another element or ion.

PHOTOELECTRIC EFFECT The emission of electrons by a sub-
stance, especially metal, when light falls on its surface.

PHOTOSYNTHESIS The process by which green plants and
some other organisms using the energy in sunlight to
convert carbon dioxide and water into carbohydrates and
oxygen.

PHOTOVOLTAIC EFFECT A type of photoelectric effect where
light is converted to electrical voltage by a substance.

PLASTICIZER A substance added to plastics to make them
stronger and more flexible.

POLYAMIDE A polymer, such as nylon, containing recurrent
amide groups linking segments of the polymer chain.

POLYMER A substance composed of very large molecules
built up by linking small molecules over and over again.

POLYSACCHARIDE A very large molecule made of many thou-
sands of simple sugar molecules joined to each other in
long, complex chains.

xlvi CHEMICAL COMPOUNDS