1. PERFORMANCE OBJECTIVES Predict, write, and balance chemical equations Recognize types of reactions Use the Kinetic Molecular Theory explain the relationship between pressure, volume, temperature, and number of particles in a gas sample.

2. Explain the relationship between temperature and average kinetic energy. Perform calculations using the ideal gas law. Interpret Dalton’s Law of Partial Pressures and use it to calculate partial pressures and total pressures.

3. Solve gas law problems concerning changes in gas pressure, volume, or temperature. Calculate mass-volume, volume—volume and limiting reactant problems for chemical reactions Calculate percent yield

4. GASES

5. KINETIC THEORY OF MATTER Particles are in constant random motion. These particles are elements. Collisions are perfectly elastic - no loss of energy.

6. PRESSURE Due to the collisions of air molecules with each other and the surfaces of the container –and number of collisions At 25 degrees Celsius, the average speed of oxygen is 443 m/s. 4 1/2 billion collisions per second

7. PRESSURE CONTINUED # of collisions depend upon –temperature –# of particles –mass of particles barometer

8. Pressure continued Speed of gas particles depends upon temperature and mass of particles Kinetic energy temperature

9. TEMPERATURE Kelvin formula practice conversions standard temperature

10. STANDARD PRESSURE Average pressure at sea level

11. UNITS OF PRESSURE mmHg kPa atm torr psi

12. STP Temperature and pressure where gases behave most ideally ideal gas

13. CHARLES’ LAW Statement of law Formula A 225 cm 3 volume of gas is collected at 58 degrees Celsius. What volume would this sample of gas occupy at standard temperature? Assume a constant pressure.

14. BOYLE’S LAW Statement of law formula A gas is collected in a 242 cm 3 container. The pressure of the gas in the container is measured and determined to be 87.6 kPa What is the volume of this gas at standard atmospheric pressure? Assume that the temperature remains constant.

15. DALTON’S LAW Statement of the law In a gas mixture, each type of gas exerts pressure that contributes to the total pressure. Each gas acts alone. Gas collected by bubbling it through water: –gas must be insoluble in water –water vapor is collected with gas –must remove pressure exerted by water

16. SAMPLE PROBLEM A quantity of gas is collected over water at 8 degrees Celsius in a 353 cm 3 container. The manometer indicates a pressure of 84.5 kPa. What volume would the dry gas occupy at standard atmospheric pressure and 8 degrees Celsius?

17. COMBINED GAS LAW Calculations involving situations in which both the temperature and pressure varies. Formula The volume of a gas measured at 75.6 kPa pressure and 60.0 degrees Celsius is to be corrected to correspond to the volume it would occupy at STP. The measure volume of the gas is 10.0 cm 3.

18. DIFFUSION OF GASES Varies according to –speed of molecules –smaller masses diffuse faster used to separate gases from each other Graham’s Law Formula

19. SAMPLE PROBLEM Find the relative diffusion for the gases krypton and bromine.

20. AVOGADRO’S PRINCIPLE At equal temperatures and pressures, equal volumes of gases contain the same number of molecules. This allows us to calculate the molar volume of a gas, Molar volume - volume occupied of by 1 mole of any gas under standard conditions. 22.4 dm 3

21. IDEAL GAS LAW Allows one to combine all 4 variables concerned with the physical characteristics of gases: –temperature –volume –pressure –number of particles

22. FORMULA PV = nRt n = number of moles R = a constant Values for R 8.31 dm3  kPa/mol  K 0.0821 liter  atm/mol  K

23. SAMPLE PROBLEMS What pressure is exerted by 4.50 moles of gas in a 198 dm 3 container at a temperature of 8 degrees Celsius? What volume would be occupied by 3.22 moles of gas at a temperature of 35 degrees Celsius and a pressure of 93.2 kPa?

24. SAMPLE PROBLEMS CONTINUED How many moles of gas can be contained in a 1.44 dm 3 container at a temperature of 32 degrees Celsius and 93.5 kPa? What temperature in degrees Celsius is a gas if 2.31 moles of it in a occupy 61dm 3 container at 94.6 kPa?

25. MOLECULAR MASS/WEIGHT Use Ideal Gas Law to determine the molecular mass of a gas from laboratory measurements. Useful in identifying an unknown gas. Formula apply formula to ideal gas law

26. SAMPLE PROBLEM Suppose we measured the mass of the vapor of an unknown compound contained in a 273 cm 3 gas bulb. We find that the bulb contains 0.750 grams of gas at 97.2 kPa pressure and 61 degrees Celsius. What is the molecular mass of the gas?

27. GAS STOICHIOMETRY What volume of hydrogen at STP can be produced when 6.54 grams of zinc react with hydrochloric acid?

28. GAS LIMITING AND EXCESS How many grams of carbon dioxide are formed of 10.0 grams of carbon are burned in 20.0 dm 3 of oxygen. Assume STP.

29. Gay-Lussac’s Law Statement of the law Formula Sample problem: The gas in an aerosol can is at a pressure of 3 atms at 25 o C. Directions on the can warn the user not to keep the can in a place where the temperature exceeds 52 o C. What would the gas pressure in the can be at 52 o C?