1. Thermochemistry

2. What is energy? The ability to do work or produce heat.

3. What are the two forms of energy? Potential and kinetic

4. What is kinetic energy? The energy of motion.

5. What is potential energy? Stored energy.

6. What is the law of conservation of energy? Energy can not be created or destroyed, it is transferred.

7. What is chemical potential energy? Energy that is stored in chemical bonds.

8. What does chemical potential energy do? It is used in chemical reactions or solution making. Ethanol

9. What is heat? Energy that flows from a warmer object to a colder one.

10. How does heat always flow? From hotter to colder.

11. What is the difference between heat and temperature? Heat is an energy that flows, temperature is the measure of the kinetic energy

12. What is a thermometer? A device used to measure the amount of kinetic energy in something (temperature).

13. What is thermochemistry? It is the study of heat changes in chemical reactions and phase changes.

14. What is exothermic? When heat exits a system (it feels warm)

15. What is endothermic? When heat enters a system (it feels cold)

16. Where does your body get energy to heat itself? From Calories in your food.

17. Why was Calorie capitalized? To tell the difference between calorie and Calorie.

18. What is a calorie? The amount of energy needed to raise the temperature of 1 gram of water 1 o C.

19. What does 1 Calorie equal? 1 nutritional Calorie equals 1000 calories.

20. A tablespoon of butter contains 125 Calories. How many calories is that?

21. What unit is used to measure energy? Joule (J)

22. What is the conversion between calories and joules? 1 calorie = 4.184 joules

23. How to Convert https://www.youtube.com/watch?v=P2D9s cG0VyMwww.youtube.com/watch?v=P2D9s cG0VyM

24. Burning 1.00 g of glucose releases 15.6 kJ of energy. How many Calories are released?

25. How many Joules are in one can of soda, which contains 255 Calories?

26. What is specific heat? The amount of energy needed to raise the temperature of one gram of the substance 1 o C.

27. What is the specific heat of water? 4.184 J/g o C

28. Do different chemicals have different specific heats? Yes. Everything is different.

29. Which has cooler feet?

30. Why? The specific heat of concrete is smaller, so it heats faster.

31. How do you calculate heat absorbed? With an equation

32. What is the equation? q= mcΔT

33. What do the letters mean? q = heat absorbed (+) or released (-) (J) c = specific heat of that substance (J/g°C) m = mass of the sample (g) ΔT = change in temperature ( o C)

34. How do you solve for Δ? Final minus initial temperature.

35. What number is given to you? c, the constant.

36. What c value do I need to memorize? The specific heat for water, 4.184 J/g o C

37. What about the other specific heats? They will be given in the problem.

38. How to do the math! https://www.youtube.com/watch?v=vq6fez KLq0Ewww.youtube.com/watch?v=vq6fez KLq0E

40. If 43.0g of water at 28°C absorbs 1605 J of heat energy, what will be the final temperature of the water?

41. What is calorimetry? Studying the amount of heat transferred from calories.

42. What is a calorimeter? An insulated device that is used to measure the amount of heat absorbed or released during a chemical reaction.

43. What is a bomb calorimeter? A calorimeter that is completely sealed off to the outside world.

44. Who uses bomb calorimeters? Food researchers to examine how many Calories are in food.

45. How do they work?

46. What are the parts of a calorimeter? The system and the surroundings.

47. What is the system? The item that you want to study, where the reaction occurs.

48. What are the surroundings? Everything in the surrounding except the system.

49. What is the universe? The system plus the surroundings.

50. If something feels cold, what type of reaction is it? Endothermic

51. If something feels hot, what type of reaction is it? Exothermic

53. What is the heat lost or gained by a system called? Change in enthalpy

54. What is enthalpy? The heat content of a system.

55. What is the change in enthalpy? ΔH (q is actually the same as ΔH)

56. When ∆H is positive, what kind of reaction do you have? Endothermic Heat is a reactant

57. Why? Heat is entering the system. (gaining energy)

58. When ∆H is negative what kind of reaction do you have? Exothermic Heat is a product

59. Why? Heat is exiting the system. (losing energy)

60. Al + HCl  H 2 + AlCl 3 ΔH= -234KJ N 2 + F 2  Energy + NF 3 SO 2 + Li 2 Se + 34.6KJ  SSe 2 + Li 2 O NH 3 + H 2 SO 4  Heat + (NH 4 ) 2 SO 4

61. Which of the phase changes are endothermic? Melting Sublimation Evaporation

62. Why are they endothermic? Heat is ENTERING the system They are gaining heat

63. Which of the phase changes are exothermic? Freezing Deposition Condensation

64. Why are they exothermic? Heat is EXITING the system They are getting colder

65. Water releases a lot of heat as it cools. During freezing weather, farmers protect citrus crops by spraying them with water.

66. What is ∆H for the reaction? It is the difference between the final and initial heat in the chemical reaction.

67. What does ΔH tell us? How much heat is released or absorbed (in kilojoules) in the substance.

68. What do we do with this information? Use it to solve problems that tell us how much heat is released or absorbed in a reaction.

69. Quick Tip! The ΔH is dependent upon the moles in the equation. Use the balanced equation to see how many moles to use for the conversion factor.

70. How to do the math! https://www.youtube.com/watch?v=8m_F Ce5aCqY https://www.youtube.com/watch?v=8m_F Ce5aCqY STOP AT 7:34!

71. Example How much heat is released when 18.6 g of hydrogen reacts with excess oxygen according to the following reaction: H 2 +O 2  H 2 O ΔH= -571.6 kJ