http://www.ck12.org Chapter 27. Glossary
in chemical systems.
physical property
The characteristic of a substance that can be observed or measured without changing the identity of the
substance.
pi bond (π)
A bond formed by the overlap of orbitals in a side-by-side fashion with the electron density concentrated
above and below the plane of the nuclei of the bonding atoms.
pOH
The negative logarithm of the hydroxide-ion concentration in a solution.
polar covalent bond
A covalent bond in which the atoms have an unequal attraction for electrons, and so the sharing is unequal.
polar molecule
A molecule in which one end of the molecule is slightly positive, while the other end is slightly negative.
polyatomic ion
An ion composed of more than one atom.
polymer
A large molecule formed of many smaller molecules covalently bonded in a repeating pattern.
polypeptide
A sequence of amino acids between ten and one hundred in length.
polyprotic acid
An acid that contains multiple ionizable hydrogens.
polysaccharide
A complex carbohydrate polymer formed from the linkage of many monosaccharide monomers.
positron
A particle with the same mass as an electron, but with a positive charge.
potential energy diagram
A diagram that shows the change in potential energy of a system as reactants are converted into products.
precipitate
Solid product that forms from a reaction and settles out of a liquid mixture.
precision
The measure of how close a series of measurements are to one another.
pressure
Applied force per unit area on a surface.
primary structure
The amino acid sequence of a protein.
principal quantum number
Indicates the principal or main energy level occupied by the electron, symbolized by the lettern.
product
The substance that is present at the end of a chemical reaction.
protein
A peptide that is greater than one hundred amino acids in length
proton
A positively charged subatomic particle present in all atoms.
pure chemistry
Chemistry that is concerned with a greater understanding of the theories behind how matter is changing in
chemical reactions.