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Author:
Christene Lohse

TEKS §112.35.C (Chemistry)

(9) Science concepts. The student understands the principles of ideal gas behavior, kinetic molecular theory, and the conditions that influence the behavior of gases. The student is expected to:

(A) describe and calculate the relations between volume, pressure, number of moles, and temperature for an ideal gas as described by Boyle's law, Charles' law, Avogadro's law, Dalton's law of partial pressure, and the ideal gas law;

(B) perform stoichiometric calculations, including determination of mass and volume relationships between reactants and products for reactions involving gases;

(C) describe the postulates of kinetic molecular theory.

Tutorial

The gaseous state is one of the three phases of matter. Gases are obtained through vaporization from liquid and sublimation from solid. When a liquid vaporizes, it is often called boiling. Gases are the least dense state of matter because they contain high kinetic energy.

Avogadro's Principle, also known as Avogadro's Law, is one of the gas laws. Avogadro's Principle states that equal volume of mass at the same temperature and pressure contain the same number of molecules. This principle can be expressed in mathematical terms as volume/amount of gas = proportionality constant.

Dalton s Law states that total pressure of a gaseous mixture is equal to the sum of the partial pressures of each substance present.

Boyle's Law states that volume of a given amount of gas held at a constant temperature varies inversely the with pressure. The relationship between pressure and volume of Boyle's Law is expressed in mathematical terms as P1V1=P2V2.

Charles Law states that the volume of a given mass of a gas is directly proportional to its Kevin temperature at constant pressure. In mathematical terms, the relationship between temperature and volume is expressed as V1/T1=V2/T2.

Gay-Lussac's Law states that the pressure of a given mass of gas varies directly with the Kelvin temperature when the volume remains constant. Gay-Lussac's Law is expressed in a formula form as P1/T1=P2/T2. When dealing with Gay-Lussac's Law, the unit of the temperature should always be in Kelvin.

The Combined Gas Law combines Charles Law, Boyle's Law and Gay Lussac's Law. The Combined Gas Law states that a gas pressure x volume x temperature = constant.

The Ideal Gas Law mathematically relates the pressure, volume, amount and temperature of a gas with the equation pressure x volume = moles x ideal gas constant x temperature; PV=nRT. The Ideal Gas Law is ideal because it ignores interactions between the gas particles in order to simplify the equation.