The Ideal Gas Law

Objectives:7.0 Explain the behavior of ideal gases in terms of

pressure, volume, temperature, and number of particles using Charles's law, Boyle's law, Gay-Lussac's law, the

combined gas law, and the ideal gas law.

6.0 Solve stoichiometric problems involving relationships among the number of particles, moles, and masses of reactants and products in a chemical

reaction.

Intro

What will happen to the pressure in a tire as air is added, if the volume and temperature of the tire do not change?

So the amount of gas (moles) and the pressure both change.

Remember:

Combined Gas Law: P1V1 = P2V2

T1 T2

Ideal Gas Law Since the ratio remains the same, then we

can say it is constant. We call the constant k. k is a constant based on the amount of gas

(n) present, where k = nR. (R is an experimentally determined constant, called the ideal gas constant, and equal to 0.0821 L-atm/mol-K.

Ideal gas law equation: PV=nRT

What is an Ideal Gas? A gas that follows all the gas laws When do gases not follow the gas laws?:

1. Gases tend not to behave “ideally” under very high pressures and low temperatures, as there is more inter-particular interactions.

2. Also, polar particles (like water vapor) are more attracted to each other because of their partial charges.

3. Large particles interact more.

Applying the Ideal Gas Law PV=nRT:

What is n? How can n be used to find the mass of a gas

present? From stoichiometry, what else can be

determined from n? How?????? Substitutions in the ideal gas equation:

n = mass (m)/molar mass (M) Rearrange the formula to solve for M. Density (D) = ?????

Examples & Assignment Examples: p.437 (41, 45) and p.438 (46, 50) Other Practice Problems can be used to

practice and make sure you know how to solve problems.

Assignment:

1. Section Assessment: p. 439 (53, 55)

2. 449: 97-100