1. Thursday Welcome, Practice Tests, Labs Round 2 tests Temperature & Pressure Conversions Combined Gas Law –M-4-2-1 STP Molar Volume Ideal Gas Law

2. Temperature Scales: Always Use Kelvin!

3. Convert the following to K or 0 C 0 0 C 5 K 20 0 C -50 0 C 100 K 100 0 C

4. Gas Laws Charles’s Law Boyle’s Law Combined Gas Law

5. Pressure vs Volume vs Temp P V V T T P P/V = k T/V = k P/T = k

6. Primetime T. V. PTV

7. Equations on your reference sheets

8. Boyles Law

9. Charles’s Law What are the units for Temperature?

10. Friday Welcome PTA Gas Laws (Green) Balancing Chemical Equations Combined Gas Law Problems –M-4-2-1 Ideal Gases

11. Combined Gas Law NOTE: Any variable left constant in a problem can be taken out of the equation. Therefore it isn’t necessary to memorize Charles’s or Boyle’s Laws.

12. Ex. 1. A container at 1 atmosphere pressure and 30 0 C is compressed from a volume of 5.7L to 3.4L and cooled to 15 0 C. What is the new pressure on the container?

13. M. What is the new volume of 4.4 L of a gas that is cooled from 20 0 C down to -50 0 C when the pressure is kept constant?

14. 4. A gas sample at room temperature (20 0 C) and 1 atm pressure occupies a 5L container. What is the new temperature if the gas is allowed to expand to a 40L container and pressure is lowered to 0.5 atm?

15. 2. A sample of Oxygen gas was compressed at constant temperature from 10L to 100ml. What is the final pressure if the initial pressure was 2 atm.

16. 1. A gas is collected in a 200 ml container at 20 o C. What was the pressure in the container if the gas is expanded to a 300 mL container at 80 o C and a pressure of 2 atm.

17. Friday Welcome: Stoichiometry Test 2 Ideal Gases –What makes a gas Ideal? –What can be do with an ideal gas?

18. Ideal Gas Laws Equation: PV = nRT A.K.A.: “PiV-neRT” Where: P= Pressure V= Volume n= moles of gas R= ideal gas constant T= Temperature An Ideal gas has particles that take up no space and have no intermolecular forces.

19. Ex. 7. Calculate the number of moles of gas contained in 3.0L vessel at 300 K with a pressure of 1.50 atm. Choose the correct value for R

20. Ex. 8. How many moles of a gas are in a 5L container at 101 kPa and 400K? ANSWER: 0.15 mol

21. PV=nRT and Mass? Ex. 9 What is the mass of Helium gas that is in a 4.3L container at 0.94 atm and 32 0 C?

22. Modify Ideal Gas to include density Equation: MP = DRT mnemonic: “Myers Park equals DiRT! Where: M = molar mass P = Pressure D = Density R = Gas Constant T = Temperature

23. What is the molar mass of an ideal gas that has a density of 1.40 g/L at STP? 1.Analyze the problem: Equation: MP = DRT 2. Determine what you have/need. M = x (unknown) P = 1 atm D = 1.40 g/L T = 0.0 o C = 273.15 K 3. Solve for the Unknown: M = DRT/P 4. Evaluate: M = (1.40g/L)(0.0821L*atm/(mol*K))(273 K)/(1 atm) = 31.4 g/mol

24. STP: Standard Temperature and Pressure 0.0 o C 1 atm

25. Molar Volume What is the volume of 1 mole of gas at STP?

26. Avogadro’s principle: equal volumes of gases at the same temperature and pressure contain equal numbers of particles. Molar Volume: Volume that one mole of gas occupies at STP. Conversion Factor: 22.4 L 1 mol

27. Ex. 6. How many moles of a gas are present in a container that is 10L at STP?

28. Gas Stoichiometry When gases are involved in a chemical reaction, the coefficients of the balanced chemical equation represent molar amounts AND relative volumes. Example: 2H 2 0 = 2H 2 (g) + O 2 (g)

30. Volume: Volume Stoichiometry CH 4 (g) + 2O 2 (g)  CO 2 (g) + 2H 2 O (g) What volume of methane is needed to produce 26 L of water vapor? 26 L H 2 O x 1 CH 4 2 H 2 O

31. Volume: Volume Stoichiometry C 3 H 8 (g) + 5O 2 (g)  3CO 2 (g) + 4H 2 O (g) What volume of carbon dioxide is produced when 5 liters of propane is combusted with excess oxygen?

32. Volume: Mass Stoichiometry N 2 (g) + 3H 2 (g)  2NH 3 (g) If 5.00 L of nitrogen reacts completely by this reaction at a constant pressure and temperature of 3.00 atm and 298 K, how many grams of ammonia are produced?

33. M What is the mass of Magnesium Oxide produced when 50 ml of oxygen are consumed at STP?

34. 3 What volume of hydrogen is produced when 10 g of calcium react with excess hydrochloric acid at STP?

35. 2 What is the mass of ammonia produced when 20 L of nitrogen are reacted with an excess of hydrogen?

36. 1 What is the volume of water produced when 56 g of oxygen react with excess hydrogen at STP?