1 / 84

Energy

Energy. Chap. 16. Definitions. Definitions. Energy. Energy is the ability to do work or produce heat. Definitions. Energy Heat. Heat is energy moving from one place to another. Heat = Energy. For us, these terms will be used synonymously. Definitions. Energy Heat Temperature.

cahil
Download Presentation

Energy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Energy Chap. 16

  2. Definitions

  3. Definitions • Energy Energy is the ability to do work or produce heat

  4. Definitions • Energy • Heat Heat is energy moving from one place to another

  5. Heat = Energy For us, these terms will be used synonymously

  6. Definitions • Energy • Heat • Temperature A measure of the kinetic energy of the particles in a substance

  7. Definitions • Energy • Heat • Temperature • Endothermic A description of a process that absorbs heat

  8. Definitions • Energy • Heat • Temperature • Endothermic • Exothermic A description of a process that gives off heat

  9. Types of Energy • Kinetic Energy of motion

  10. Types of Energy • Kinetic • Mechanical Moving objects

  11. Types of Energy • Kinetic • Mechanical • Thermal Heat energy (moving particles)

  12. Types of Energy • Kinetic • Potential Stored energy

  13. Types of Energy • Kinetic • Potential • Gravitational Energy that can be released as gravity acts

  14. Types of Energy • Kinetic • Potential • Gravitational • Chemical Energy stored in chemical bonds

  15. Types of Energy • Kinetic • Potential • Radiant Energy in the form of light

  16. Measuring Heat (q)

  17. Measuring Heat (q) • Units

  18. Measuring Heat (q) • Units • joule SI unit of energy (work). Work done by applying one Newton force over one meter.

  19. Measuring Heat (q) • Units • joule • calorie Energy required to heat one gram of water by 1° C.

  20. Measuring Heat (q) • Units • joule • calorie • Calorie A nutritional calorie. 1 Cal = 1000 cal

  21. Measuring Heat (q) • Units • joule • calorie • Calorie • kilocalorie Equivalent to calories

  22. Measuring Heat (q) • Units • joule • calorie • Calorie • kilocalorie Equivalent to 1000 calories

  23. Measuring Heat (q) • Units • joule • calorie • Calorie • kilocalorie • BTU Energy required to heat 1 lb. water by 1º F.

  24. Heat Unit Conversions 1 cal = 4.184 J 1000 cal = 1 Cal = 1 kcal

  25. Self Check – Ex. 1 A reaction produces 3800 J of heat. How many calories is this?

  26. Self Check – Ex. 2 A can of soda contains 150 Calories. How many joules of energy is this?

  27. Measuring Heat (q) • Units • Heat is related to temperature

  28. Measuring Heat (q) • Units • Heat is related to temperature Temp. = 35º C Temp. = 65º C Beaker #1 Beaker #2 Which has more heat?

  29. Measuring Heat (q) • Units • Heat is related to temperature • Heat also depends on. . .

  30. Measuring Heat (q) • Units • Heat is related to temperature • Heat also depends on. . . • Mass of material

  31. Which beaker could melt more ice (which has more heat)? T2 = 85º C T1 = 85º C Beaker #1 Beaker #2

  32. Measuring Heat (q) • Units • Heat is related to temperature • Heat also depends on. . . • Mass of material • Type of material

  33. Measuring Heat (q) • Units • Heat is related to temperature • Heat also depends on. . . • Specific Heat Amount of heat required to raise the temperature of 1 gram of substance by 1º C

  34. Measuring Heat (q) • Units • Heat is related to temperature • Heat also depends on. . . • Specific Heat • Some material takes a lot of energy to raise its temperature

  35. Measuring Heat (q) • Units • Heat is related to temperature • Heat also depends on. . . • Specific Heat • Some material takes a lot of energy to raise its temperature • Some material takes less

  36. Measuring Heat (q) • Units • Heat is related to temperature • Heat also depends on. . . • Specific Heat • Some material takes a lot of energy to raise its temperature • Some material takes less • For water it’s 1 calorie/g ºC

  37. Specific Heat Table SubstanceSpec. Heat (c) Water 4.184 J/g ºC Aluminum 0.89 J/g ºC Iron 0.45 J/g ºC Copper 0.387 J/g ºC Silver 0.24 J/g ºC Gold 0.129 J/g ºC Lead 0.l28 J/g ºC

  38. Measuring Heat (q) • Units • Heat is related to temperature • Heat also depends on. . . • Specific Heat • Calculation q = m x c x∆T

  39. Self Check – Ex. 3 How much heat must be applied to a 25 g chunk of iron to raise its temperature by 100ºC? (ciron = 0.45 J/g ºC)

  40. Self Check – Ex. 4 How much heat must be applied to a 25 g sample of water to raise its temperature by 100ºC? (ciron = 4.18 J/g ºC)

  41. Bond Energy

  42. Bond Energy • When bonds are broken energy is . This is endothermic

  43. Bond Energy • When bonds are broken energy is required. (positive) This is endothermic

  44. Bond Energy • When bonds are broken energy is required. (positive) • When bonds are formed energy is .

  45. Bond Energy • When bonds are broken energy is required. (positive) • When bonds are formed energy is released. (negative) This is exothermic

  46. Bond Energy • When bonds are broken energy is required. (positive) • When bonds are formed energy is released. (negative) • The sum of the bond energies gives an estimate of the reaction energy

  47. Bond Energy • When bonds are broken energy is required. (positive) • When bonds are formed energy is released. (negative) • The sum of the bond energies gives an estimate of the reaction energy • Positive values = endothermic

  48. Bond Energy • When bonds are broken energy is required. (positive) • When bonds are formed energy is released. (negative) • The sum of the bond energies gives an estimate of the reaction energy • Positive values = endothermic • Negative values = exothermic

  49. Self Check – Ex. 5 Draw Lewis structures for each substance and calculate the energy for the reaction below. 2CO + O2 2CO2

  50. Enthalpy Stoichiometry

More Related