Entropylessoningeneralchemistrymelcs.pptx
- 1. Spontaneous Process and Entropy Grade 12 STEM General Chemistry 2
- 2. Background information Chemical Thermodynamics: the study of the interrelation of heat and work with chemical reactions or with physical changes of state within the confines of the laws of thermodynamics. Thermodynamics: Is a scientific discipline that deals with the interconversion of heat and other forms of energy.
- 4. Laws of Thermodynamics First Law Energy of the universe is constant. “Energy can be converted from one form to another, but it can never be created nor destroyed” Second Law Entropy of universe increases. “The entropy of the universe increases in a spontaneous process and remains unchanged in the equilibrium Third Law At absolute zero, the entropy of a perfect crystal is 0. “The entropy of the perfect crystalline substance is zero at the absolute zero of temperature (T = 0, K = -273.150C).”
- 5. 2nd Law Spontaneous process as stated in the second law is a physical or chemical change that occurs by itself.
- 6. 2nd Law A process that takes place without energy from an external source.
- 7. 2nd Law It is the time-evolution of a system which releases free energy and it moves to a lower, more thermodynamically stable energy state.
- 8. Spontainity If heat flows into surroundings (exothermic) the random motion of the molecules in the surroundings increases. Thus, the entropy of the surroundings increases.
- 9. ENTROPHY 02
- 10. Entrophy Is a thermodynamic quantity that is a measure of randomness and disorder.
- 11. Entrophy It measures how spread out or dispersed the energy of a system is among the different possible ways that system can contain energy.
- 12. Entrophy It tells whether a process or chemical reaction can occur.
- 13. Entrophy It tells whether a process or chemical reaction can occur.
- 14. Entrophy and Spontainity The connection between entropy and the spontaneity of a reaction is expressed by the second law of thermodynamics.
- 15. Change in Entrophy The change in entropy for a given amount of heat absorbed also depends on temperature.
- 16. Change in Entrophy If the temperature of the surroundings is high, the molecules are already quite energetic. Hence, the absorption of heat from an exothermic process in the system will have relatively little impact on the motion of the molecules causing a decrease in entropy
- 17. Change in Entrophy iIf the temperature of the surroundings is low, than the addition of the same amount of heat will cause a more drastic increase in molecular motion and hence a larger increase in entropy.
- 18. Example: Consider the phase changes illustrated bellow. At higher temperatures, the distribution of kinetic energies among the atoms or molecules of the substance is also broader (more dispersed) than at lower temperatures. Thus, the entropy for any substance increases with temperature.
- 19. Example: Consider the phase changes illustrated bellow. The entropy of a substance increases (ΔS > 0) as it transforms from a relatively ordered solid, to a less- ordered liquid, and then to a still less-ordered gas. The entropy decreases (ΔS < 0) as the substance transforms from a gas to a liquid and then to a solid.
- 20. Example: What did you observe?
- 21. Example: 1. What can you say about the pictures? Compare the pictures in each set. Pictures at the left is rock rolling down a hill while at the right is a rock pushing up a hill.
- 22. Example: Compare the pictures in each set. 3. Which one is more spontaneous? Why? Pictures at the left is more spontaneous because it moves without any outside intervension. The speed at which is occurs governed by kinetics.
- 23. Example: Compare the pictures in each set. 2. How do you compare the pictures? The rock rolling down a hill occurs without any intervention while rock at the right need to apply force to make the rock roll and ski up the hill.
- 24. Activity 03
- 25. Spontainity : Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. 1. Rusting of iron in moist air 6. Drying of leaves 2. Decaying of radioisotopes 7. Dissolving of salt 3. Oxidation of gold 8. Radioactive atom splits up 4. Spoilage of food 9. Dissolution of sand in 5. Burning of chlorine water 10. Fireworks
- 26. Spontainity Answer: Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. Rusting of iron in moist air Spontaneous
- 27. Spontainity Answer: Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. Decaying of radioisotopes Spontaneous
- 28. Spontainity Answer: Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. Oxidation of gold Not Spontaneous
- 29. Spontainity Answer: Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. Spoilage of food Spontaneous
- 30. Spontainity Answer: Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. Burning of chlorine Not Spontaneous
- 31. Spontainity Answer: Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. Drying of leaves Spontaneous
- 32. Spontainity Answer: Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. Dissolving of salt Spontaneous
- 33. Spontainity Answer: Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. Radioactive atom splits up Spontaneous
- 34. Spontainity Answer: Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. Dissolution of sand and water Spontaneous
- 35. Spontainity Answer: Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. Dissolution of sand and water Not Spontaneous
- 36. Spontainity Answer: Directions: Classify the given situations below whether the process is spontaneous or not- spontaneous. Fireworks Spontaneous
- 37. Assignmen t
- 38. WORD SEARCH Directions: Search and encircle the important terms being described in the sentences below. Words can be forward, backward, vertical, horizontal, or diagonal. 1. The scientific discipline that deals with the interconversion of heat and other forms of energy. 2. A process of a physical or chemical change that occurs by itself. 3. The measure of randomness and disorder. 4. Process that gives off heat to the surroundings. 5. Process that absorbs heat from the surroundings.
- 39. WORD SEARCH Directions: Search and encircle the important terms being described in the sentences below. Words can be forward, backward, vertical, horizontal, or diagonal. 6. The value of the product during endothermic process. 7. The value of the product during exothermic process. 8. The change of phase from solid to liquid. 9. The change of phase from liquid to gas. 10. The change of phase from solid to gas.
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