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HONORS CHEMISTRY

HONORS CHEMISTRY. May 7, 2012. Brain Teaser. Turn in Titration Lab Describe the characteristics or properties of solid, liquid and gases. Agenda. Brain Teaser Unit 9 Acid/Base Test Result Notes: Introduction to Gases and Gas Laws Homework Charles and Boyles Law Worksheet.

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HONORS CHEMISTRY

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  1. HONORS CHEMISTRY May 7, 2012

  2. Brain Teaser • Turn in Titration Lab • Describe the characteristics or properties of solid, liquid and gases

  3. Agenda • Brain Teaser • Unit 9 Acid/Base Test Result • Notes: Introduction to Gases and Gas Laws • Homework • Charles and Boyles Law Worksheet

  4. Introduction to Gases • Earth is surrounded by a layer of gaseous molecules - the atmosphere - extending out to about 50 km.

  5. Characteristics of Gases • Gases • low density; compressible • volume = shape of container • expand when heated • large distance between particles • Model of a gas: • rapidly moving particles: vol. & shape of container • no attraction between particles • moving about freely • large space between particles: low density & high compressibility 12m05vd1

  6. Liquids and Solids • Liquids • higher density, lower compressibility • characteristic volume; shape of container • particles closer together; moving about; experience attractive forces • Solids • high density; low compressibility • particles are close together; little empty space; strong attractive forces • characteristic volume and shape

  7. Atomic View of the States of Matter • Note distance between particles and order of arrangement of particlesFigure 9.1 01m07an1

  8. States of Matter

  9. Pressure • Pressure = force/area • Units: lb/ft2Pa = N/m2 = kg/ms2torr = mm Hgatm • 1 atm = 760 torr= 760 mm Hg1 atm = 29.9 in Hg = 14.7 lb/in21 atm = 101.3 kPa • Measure pressure with barometer or U-tube or manometer

  10. Variables/Units Held Constant Relationship (direct or inverse) In words T = K V = L P = atm n = moles Direct As temperature increases, volume increases Charles’ Law- Relationship between:_________ and __________

  11. Graph of Relationship Charles’ Law

  12. Charles’ Law Formula How to convert C to K F to C to K V/T = m m= constant V1/T1 = V2/T2 K = C + 273 C = 5/9(F-32) K = C + 273 Charles’ Law

  13. Temperature Conversion Practice Practice Problem Convert 212 degrees F to K Convert 50 degrees C to K The volume of a sample of gas is 2.50L at 45K. What is the volume when it is heated to 125K at a constant pressure. Charles’ Law

  14. Pressure • Why does a pin hurt? • Why don’t snowshoes sink?

  15. Variables/Units Held Constant Volume (L) Pressure (atm) Temperature (K) Moles (n) Boyle’s Law: The relationship between _______ & ________

  16. Relationship (direct or inverse) Relationship in words Inverse As pressure increases volume decreases. Boyle’s Law:

  17. Sketch Graph Pressure vs. Volume Boyle’s Law

  18. Sketch Graph Pressure vs. 1/ V Boyle’s Law

  19. Boyle’s Law Formula Pressure Units PV = m m = constant P1V1 = P2V2 atm = atmospheres mmHg = millimeters of mercury torr Pa = Pascals psi = pounds per square inch 1 atm = 101,325Pa = 760 mmHg = 760 torr = 14.70psi Boyle’s Law Formula

  20. Pressure Unit Conversions 1 atm = 101,325Pa = 760 mmHg = 760 torr = 14.70psi Boyle’s Law Formula

  21. How to convert from pressure units to atm (use dimensional analysis) Convert 458mmHg to atm Convert 96.5 psi to atm Convert 485kPa to atm Boyle’s Law

  22. Boyle’s Law Practice Problem The pressure on 2.5L of anesthetic gas is changed from 760mmHg to 304mmHg. What will be the new volume of the gas? Boyle’s Law

  23. STP: Standard Temperature and Pressure • 0 oC (273 K) , 1 atm

  24. HONORS CHEMISTRY (5/6)

  25. Open Note Quiz (5/6) • Place Homework on your desk • Textbook Notes • Charles and Boyles’ Laws Worksheet • Time – 10 minutes

  26. Unit Conversion for Gas Laws Calculations • Convert to the following units P = atm V = Liters T = Kelvin (oC + 273)

  27. Agenda • Open Note Quiz • Grade Homework • Charles & Boyles’ Laws Worksheet • Exploring Gas Behavior

  28. Exploring Gas Behavior Activity • Refer to Handout

  29. HONORS CHEMISTRY May 11, 2012

  30. Brain Teaser • The pressure on 5.5 L gas is changed from 3 atm to 5 atm. What will be the new volume of the gas? • The volume of a sample of gas is 4 mL at 40oC. What is the volume when it is heated to 60 oC at a constant pressure?

  31. Agenda • Brain Teaser • Grade Worksheet: Charles and Boyles’ Law Worksheet • Notes: Combined Gas law, Avogadro’s Law and Ideal Gas Law • Homework • Ideal Gas Law and Combined Gas Law Worksheet

  32. Combined Gas Law Boyle’s Law Charles’s Combined

  33. Avogadro’s Law • How can we change the volume of a gas in a balloon?

  34. Avogadro’s Law • Why did the blimp deflate?

  35. V n Avogadro’s Law • If the pressure and temperature are held constant, the volume of a gas is directly proportional to the number of moles (n).

  36. Gas Laws Part 2: Work on Gas Notes Sheet instead of Brain Teaser Avogadro’s Law O2 O3 Suppose we have a 12.2 L sample containing 0.50 mol oxygen gas at a pressure of 1 atm and a temperature of 25 ºC. 1) Balance the equation 2) If all this oxygen is converted to ozone at the same temperature and pressure, what would be the volume of the ozone?

  37. Dalton's Law • The total pressure is the sum of the partial pressures. • Ptotal = P1 + P2 + P3 + …..

  38. Dalton’s Law Practice • A mixture of oxygen, carbon dioxide, and nitrogen has a total pressure of 0.97atm. What is the partial pressure of Oxygen, if the partial pressure of carbon dioxide is 0.70atm and the partial pressure of nitrogen is 0.12atm?

  39. The Gas Laws • Variables: V, P, T, n (or m and MM or d) • Ideal Gas: properties are independent of the identity of the gas • What is the relationship between the variables for an ideal gas? Basketball Bike Tire

  40. 5.3 Ideal Gas Law • PV = nRT • P= pressure • V = volume • n = number of moles • R = ideal gas constant • 0.08206 L·atm/mol·K • T = temperature

  41. STP • Standard Temperature and Pressure • 0ºC and 1 atm • Use the Ideal Gas Law to calculate the volume of 1.00 mol of gas at STP

  42. Molar Volume at STP • We can show that 22.414 L of any gas at 0C and 1 atm contain 6.02  1023 gas molecules.

  43. Example • A sample of Hydrogen gas has a volume of 8.56 L at 0ºC and a pressure of 1.5 atm. Calculate the moles H2 molecules present in this gas sample.

  44. Practice Problem • The volume of an oxygen cylinder is 1.85 L. What mass of oxygen gas remains in the cylinder when it is “empty” if the pressure is 755 torr and the temperature is 18.1oC? • Answer: 2.46 g

  45. Gas Law Stoichiometry • Quicklime (CaO) is produced by the thermal decomposition of calcium carbonate. Calculate the volume of CO2 at STP produced from the decomposition of 152 g of CaCO3 by the reaction • CaCO3 (s) CaO (s) + CO2 (g)

  46. Molar Mass and the Ideal Gas Law • If 0.126 g of a gas are contained in a 25mL tank at 25ºC and 3.25 atm, what is the molar mass of the gas? What is the gas?

  47. Kinetic Molecular Theory • A model that attempts to explain the behavior of an ideal gas. • The particles are so small that compared with the distances between them that the volume of the individual particles can be assumed to be negligible (zero). • The particles are in constant motion. The collisions of the particles with the walls of the container are the cause of the pressure exerted by the gas.

  48. Kinetic Molecular Theory • The particles are assumed to exert no forces on each other; they are assumed to neither attract nor repel each other. • The average kinetic energy of a collection of gas particles is assumed to be directly proportional to the Kelvin temperature of the gas.

  49. When does the Kinetic Molecular Theory break down? • What conditions would cause our assumptions to become in valid?

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