14.1. The Ideal Gas Law http://www.ck12.org
14.1 The Ideal Gas Law
Objectives
The student will:
- Explain the Ideal Gas Law.
- Solve problems using the Ideal Gas Law.
Vocabulary
- Avogadro’s number:The constant, 6. 022 × 1023 , representing the number of atoms in a gram atom, or the
number of molecules in a gram molecule. - Boyle’s Law: States that the absolute pressure and volume of a given mass of confined gas are inversely
proportional, if the temperature remains unchanged within a closed system. Thus, it states that the product of
pressure and volume is a constant for a given mass of confined gas as long as the temperature is constant, PV
= k when T = k. The law was named after chemist and physicist Robert Boyle, who published the original law
in 1662. - Charles’s Law:An experimental gas law which describes how gases tend to expand when heated. A modern
statement of Charles’ Law is: At constant pressure, the volume of a given mass of an ideal gas increases or
decreases by the same factor as its temperature on the absolute temperature scale (i.e. the gas expands as the
temperature increases).V=kT - Guy-Lussac’s Law: The pressure of a gas of fixed mass and fixed volume is directly proportional to the
absolute temperature of the gas.PT=k - Ideal Gas Law:A law that describes the relationships between measurable properties of an ideal gas. The
law states that P×V = n×(R)×T, where P is pressure, V is volume, n is the number of moles of molecules,
T is the absolute temperature, and R is the gas constant (8.314 Joules per degree Kelvin or 1.985 calories per
degree Celsius). A consequence of this law is that, under constant pressure and temperature conditions, the
volume of a gas depends solely on the number of moles of its molecules, not on the type of gas. This is also
called the Universal Gas Law. - mole: A unit of measurement used in chemistry to express amounts of a chemical substance. A mole is
defined as an amount of a substance that contains as many elementary entities (e.g., atoms, molecules, ions,
electrons) as there are atoms in 12 grams of pure carbon-12 (^12 C), which is the isotope of carbon with atomic
weight 12. This corresponds to a value of 6. 02214179 × 1023 elementary entities of the substance. It is one of
the base units in the International System of Units, and has the unit symbol mol. - molecular mass:The mass of a molecule.