27.16. P http://www.ck12.org
27.16 P
partial pressure
The contribution that gas makes to the total pressure when the gas is part of a mixture.
pascal (Pa)
The standard unit of pressure.
Pauli exclusion principle
A principle that states that no two electrons in an atom can have the same set of four quantum numbers.
peptide
A combination of amino acids in which the amino group of one amino acid has undergone a reaction with the
carboxyl group of another amino acid.
peptide bond
The amide bond that occurs between the amino nitrogen of one amino acid and the carboxyl carbon of another
amino acid
percent composition
The percent by mass of each element in a compound.
percent error
The absolute value of the error divided by the accepted value and multiplied by 100%.
percent yield
The ratio of the actual yield to the theoretical yield, expressed as a percentage.
period
A horizontal row of the periodic table.
periodic law
A law that states that when elements are arranged in order of increasing atomic number, there is a periodic
repetition of their chemical and physical properties
periodic table
The arrangement of the elements in order of their atomic numbers so that elements with similar properties
appear in the same vertical column or group.
pH
The negative logarithm of the hydrogen-ion concentration in a solution.
phase
Any part of a sample that has a uniform composition and properties.
phase diagram
A graph which the conditions of temperature and pressure under which a substance exists in the solid, liquid,
and gas.
phospholipid
A lipid that contains a phosphate group and is a major component of cell membranes.
photoelectric effect
A phenomenon that occurs when light shined onto a metal surface causes the ejection of electrons from that
metal.
photon
A particle of electromagnetic radiation that has zero mass and carries a quantum of energy.
physical change
A change to a sample of matter in which some properties of the material change, but the identity of the matter
does not.
physical chemistry
A branch of chemistry that is the study of the both the macroscopic and the atomic properties and phenomena