3. Chapter Menu Gases Section 13.1Section 13.1The Gas Laws Section 13.2Section 13.2 The Ideal Gas Law Section 13.3Section 13.3 Gas Stoichiometry Exit Click a hyperlink or folder tab to view the corresponding slides.

4. Section 13-2 Section 13.2 The Ideal Gas Law Relate number of particles and volume using Avogadro’s principle. mole: an SI base unit used to measure the amount of a substance; the amount of a pure substance that contains 6.02 × 10 23 representative particles Relate the amount of gas present to its pressure, temperature, and volume using the ideal gas law. Compare the properties of real and ideal gases.

5. Section 13-2 Section 13.2 The Ideal Gas Law (cont.) Avogadro’s principle molar volume ideal gas constant (R) ideal gas law The ideal gas law relates the number of particles to pressure, temperature, and volume.

6. Section 13-2 Avogadro's Principle Avogadro’s principle states that equal volumes of gases at the same temperature and pressure contain equal numbers of particles.Avogadro’s principle

7. Section 13-2 The Ideal Gas Law (cont.) The ideal gas law describes the physical behavior of an ideal gas in terms of pressure, volume, temperature, and amount.ideal gas law P 1 V 1 P 2 V 2 n 1 T 1 n 2 T 2 = All particles will have a direct relationship with the pressure and/or volume of the sample. PV nT = R (constant) PV = nRT

8. Section 13-2 The Ideal Gas Law (cont.) How do we find the value of the gas constant ‘R’? We measure samples of gas and insert the values into the ideal gas law equation. 1 mole of any gas at STP (Standard Temperature and Pressure) yields these values: P = 1.00 atm (standard pressure) V = 22.4 L (standard molar volume) n = 1.00 mole T = 273 K (0 o C = standard temperature)

9. Section 13-2 The Ideal Gas Law (cont.) (1.00 atm)(22.4 L) (1.00 mol)(273 K) = R PV nT = R (constant) R = 0.0821 Latm/molK This value can be used for all gas samples, but you must use the same units as the constant.

10. Section 13-2 The Ideal Gas Law (cont.) The gas law constant can be calculated for different units.

11. Section 13-2 Real Versus Ideal Gases Ideal gases follow the assumptions of the kinetic-molecular theory. Ideal gases experience: –There are no intermolecular attractive or repulsive forces between particles or with their containers. –The particles are in constant random motion. –Collisions are perfectly elastic.

12. Section 13-2 Real Versus Ideal Gases (cont.) Real gases deviate most from ideal gases at high pressures and low temperatures. Under these conditions they tend to condense into a liquid or solid state. Molecules that are highly polar will tend to deviate more because of their greater attractions for each Molecules that are large will tend to deviate more because they occupy more space.

13. Section 13-2 The Ideal Gas Law—Molar Mass and Density The IGL equation can be adapted to solve directly for the molar mass (M) of a substance if you know the mass (m) and the values for P,V, and T.

14. Section 13-2 The Ideal Gas Law—Molar Mass and Density (cont.) The IGL equation can be adapted to solve directly for the density of the gas (D) at a given T and P, if you know the molar mass.

15. A.A B.B C.C D.D Section 13-2 Section 13.2 Assessment Which of the following is NOT one of the related physical properties described in the ideal gas law? A.pressure B.volume C.density D.temperature

16. A.A B.B C.C D.D Section 13-2 Section 13.2 Assessment 3.00 mol of O 2 at STP occupies how much volume? A.30.0 L B.22.4 L C.25.4 L D.67.2 L