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Ch18.1 – Reaction Rates Reaction Rates explained by collision theory.

Ch18.1 – Reaction Rates Reaction Rates explained by collision theory. -must collide with the correct o rientation -must have enough Kinetic energy to break apart old bonds when collide.  http://www.saskschools.ca/curr_content/chem30_05/2_kinetics/kinetics2_1.htm.

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Ch18.1 – Reaction Rates Reaction Rates explained by collision theory.

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  1. Ch18.1 – Reaction Rates Reaction Rates explained by collision theory. -must collide with the correct orientation -must have enough Kinetic energy to break apart old bonds when collide.  http://www.saskschools.ca/curr_content/chem30_05/2_kinetics/kinetics2_1.htm

  2. Factors Affecting Reaction Rates “CANTC” Concentration – more particles = more collision Surface Area – more surface area= more places for rxn to occur Nature of the reactants – some substances are more reactive than others Temperature – higher temp= more KE A.E. Catalyst – Lowers activation energy (provides an alternate path) R P

  3. Factors Affecting Reaction Rates “CANTC” Concentration – more particles = more collision Surface Area – more surface area= more places for rxn to occur Nature of the reactants – some substances are more reactive than others Temperature – higher temp= more KE A.E. Catalyst – Lowers activation energy (provides an alternate path) R P Two Types of Catalysts: 1. Heterogeneous catalyst- A surface for the reaction to take place on. (Like a work bench) Platinum is the most common. 2. Homogeneous catalyst-get involved in the reaction form intermediate compounds, but come back out unchanged. Ex: The decomposition of hydrogen peroxide is slow. Iodide ions help speed it up. H202(l) H20(l) + 02(g)

  4. Reversible Reactions • 2SO2(g) + O2(g) 2SO3(g) • 1% 99% • Forward & reverse reactions occurring at same time. • When they reach the same rate, reach chemical equilibrium. • - Doesn’t have to occur in the middle (50%,50%) • Exs) H2CO3 CO2 + H2O At equilibrioum, • Products favored • 1% 99% • CaCO3CaO + CO2 At equilibrioum, • Reactants favored • 99% 1% • Ch18 HW#1 1 - 6

  5. Ch18 HW#1 1 – 6 1. Rate of reaction – 2. 1.0 mol zinc is completely converted to zinc oxide ZnO is 5.3 months. What is the average rate of conversion in mol/months 3. Refrigerated food vs. room temp food

  6. Ch18 HW#1 1 – 6 1. Rate of reaction – how fast the reaction converts reactants into products 2. 1.0 mol zinc is completely converted to zinc oxide ZnO is 5.3 months. What is the average rate of conversion in mol/months 3. Refrigerated food vs. room temp food

  7. Ch18 HW#1 1 – 6 1. Rate of reaction – how fast the reaction converts reactants into products 2. 1.0 mol zinc is completely converted to zinc oxide ZnO is 5.3 months. What is the average rate of conversion in mol/months 3. Refrigerated food vs. room temp food

  8. Ch18 HW#1 1 – 6 1. Rate of reaction – how fast the reaction converts reactants into products 2. 1.0 mol zinc is completely converted to zinc oxide ZnO is 5.3 months. What is the average rate of conversion in mol/months 3. Refrigerated food vs. room temp food Lower temp, Higher temp = higher KE slows rxn rate= higher rate of rxn

  9. 4.How does each affect rate of reaction? a. Temp b. Concentration c. Particle size d. Catalyst 5. Double arrows in equation: 6.How do the amounts of reactants & products change once a reaction has achieved equilibrium?

  10. 4.How does each affect rate of reaction? a. Temp – higher temp = higher KE = faster rate b. Concentration – greater concentration = faster rate c. Particle size – smaller particles =more surface area = faster rate d. Catalyst – lowers the activation energy = faster rate 5. Double arrows in equation: 6.How do the amounts of reactants & products change once a reaction has achieved equilibrium?

  11. 4.How does each affect rate of reaction? a. Temp – higher temp = higher KE = faster rate b. Concentration – greater concentration = faster rate c. Particle size – smaller particles =more surface area = faster rate d. Catalyst – lowers the activation energy = faster rate 5. Double arrows in equation: Represent a reversible reaction. Ex: 6.How do the amounts of reactants & products change once a reaction has achieved equilibrium? N2(g) + 3H2(g) 2NH2(g)

  12. 4.How does each affect rate of reaction? a. Temp – higher temp = higher KE = faster rate b. Concentration – greater concentration = faster rate c. Particle size – smaller particles =more surface area = faster rate d. Catalyst – lowers the activation energy = faster rate 5. Double arrows in equation: Represent a reversible reaction. Ex: 6.How do the amounts of reactants & products change once a reaction has achieved equilibrium? The amounts stay constant. The rate of the forward reaction equals the rate of the reverse reaction. N2(g) + 3H2(g) 2NH2(g)

  13. Ch18.2 – Factors Affecting Equilibrium A chemical reaction that has reached equilibrium is a delicate balance. If it’s disturbed, it will make minute adjustments to restore itself at a new equilibrium position. Le Chatelier’s Principle If stress is applied to a system at equilibrium, the system changes to relieve the stress. - Add something shifts to opposite side - Remove something shifts to the side of removal. - Adding pressure shifts to side with fewer gas particles. Decreasing pressure shifts to side with more gas.

  14. Ex1) N2(g) + 3H2(g) 2NH3(g) + heat Remove NH3(g), shifts to ________ Add N2: ________ Add heat: ________ Increase pressure: ________ Ex2) CO2(g) + H2(g) + heat CO(g) + H2O(g) Decrease temp: ________ Add heat: ________ Add H2O: ________ Increase pressure: ________

  15. Ex1) N2(g) + 3H2(g) 2NH3(g) + heat Remove NH3(g), shifts to products Add N2: products Add heat: reactants Increase pressure: products Ex2) CO2(g) + H2(g) + heat CO(g) + H2O(g) Decrease temp: reactants Add heat: products Add H2O: reactants Increase pressure: no affect

  16. Ex3) 2 SO2(g) + O2(g) 2 SO3(g) + heat Increase SO2 : ________ Increase heat: ________ Add SO3 : ________ Increase pressure : ________ Ch18 HW#2

  17. Lab18.1 – Reaction Rates - due in 2 days - Ch18 HW#2 due at beginning of period

  18. Ch18.1,18.2 Review Worksheet 1. CANTC: 2. What do catalysts do to speed up a reaction? 3. Draw catalyst path on energy diagram: 4. 2 types of catalysts:

  19. Ch18.1,18.2 Review Worksheet 1. CANTC: Concentration Surface Area Nature of the reactants Temp Catalyst 2. What do catalysts do to speed up a reaction? 3. Draw catalyst path on energy diagram: 4. 2 types of catalysts:

  20. Ch18.1,18.2 Review Worksheet 1. CANTC: Concentration Surface Area Nature of the reactants Temp Catalyst 2. What do catalysts do to speed up a reaction? Provide alternate path/lowers activation energy 3. Draw catalyst path on energy diagram: a.e. 4. 2 types of catalysts: R P

  21. Ch18.1,18.2 Review Worksheet 1. CANTC: Concentration Surface Area Nature of the reactants Temp Catalyst 2. What do catalysts do to speed up a reaction? Provide alternate path/lowers activation energy 3. Draw catalyst path on energy diagram: a.e. 4. 2 types of catalysts: R P

  22. Ch18.1,18.2 Review Worksheet 1. CANTC: Concentration Surface Area Nature of the reactants Temp Catalyst 2. What do catalysts do to speed up a reaction? Provide alternate path/lowers activation energy 3. Draw catalyst path on energy diagram: a.e. 4. 2 types of catalysts: R P Heterogeneous – provides a place for the reaction to occur Homogeneous – becomes part of the reaction mechanism then gets spit back out.

  23. 5. CaCO3(s)+ heat CaO(s)+ CO2(g) • a. CaCO3(s)added: __________ • b. Heat added: __________ • c. CaO removed: __________ • d. Pressure increased: __________ • e. Temp decreased: __________ • 6. 2H2(g) + O2(g)2H2O(g) + heat • a. H2 is added: __________ • b. Heat is added: __________ • c. O2is removed: __________ • d. Pressure is increased: __________ • e. Temp decreased: __________

  24. 5. CaCO3(s)+ heat CaO(s)+ CO2(g) • a. CaCO3(s)added: products • b. Heat added: products • c. CaO removed: products • d. Pressure increased: reactants • e. Temp decreased: products • 6. 2H2(g) + O2(g)2H2O(g) + heat • a. H2 is added: __________ • b. Heat is added: __________ • c. O2is removed: __________ • d. Pressure is increased: __________ • e. Temp decreased: __________

  25. 5. CaCO3(s)+ heat CaO(s)+ CO2(g) • a. CaCO3(s)added: products • b. Heat added: products • c. CaO removed: products • d. Pressure increased: reactants • e. Temp decreased: reactants • 6. 2H2(g) + O2(g)2H2O(g) + heat • a. H2 is added: products • b. Heat is added: products • c. O2is removed: reactants • d. Pressure is increased: products • e. Temp decreased: products

  26. 7. H2(g) + Cl2(g)2HCl(g) + 93.2kJ • a. H2 is added: __________ • b. Heat is added: __________ • c. HClis removed: __________ • d. Pressure is increased: __________ • e. Temp decreased: __________ • 8. ____CH2(g) + ____ O2(g) ____O2(g) + ___H2O(g) + 890kJ • a. CO2 is added: __________ • b. Heat is added: __________ • c. CO2is removed: __________ • d. Pressure is increased: __________ • e. Temp decreased: __________

  27. 7. H2(g) + Cl2(g)2HCl(g) + 93.2kJ • a. H2 is added: products • b. Heat is added: reactants • c. HClis removed: products • d. Pressure is increased: no effect • e. Temp decreased: products • 8. ____CH2(g) + ____ O2(g) ____CO2(g) + ___H2O(g) + 890kJ • a. CO2 is added: __________ • b. Heat is added: __________ • c. CO2is removed: __________ • d. Pressure is increased: __________ • e. Temp decreased: __________

  28. 7. H2(g) + Cl2(g)2HCl(g) + 93.2kJ • a. H2 is added: products • b. Heat is added: reactants • c. HClis removed: products • d. Pressure is increased: no effect • e. Temp decreased: products • 8. 2 CH2(g) + 3O2(g)2 CO2(g) + 2 H2O(g) + 890kJ • a. CO2 is added: __________ • b. Heat is added: __________ • c. CO2is removed: __________ • d. Pressure is increased: __________ • e. Temp decreased: __________

  29. 7. H2(g) + Cl2(g)2HCl(g) + 93.2kJ • a. H2 is added: products • b. Heat is added: reactants • c. HClis removed: products • d. Pressure is increased: no effect • e. Temp decreased: products • 8. 2 CH2(g) + 3O2(g)2 CO2(g) + 2 H2O(g) + 890kJ • a. CO2 is added: reactants • b. Heat is added: reactants • c. CO2is removed: products • d. Pressure is increased: products • e. Temp decreased: products

  30. 9. Br2(l)+ heat Br2(g) • a. Br2(g)is added: __________ • b. Heat is added: __________ • c. Br2(g) is removed: __________ • d. Pressure is decreased: __________ • e. Temp decreased: __________ • 10. Lab18.1 Alka-seltzer reaction rates: • 1. Hot, cold and room temp water affected the rate of reaction, proved: • 2. Whole, broken, and powdered tablets affected the rate of reaction, • proved: • 3. Cork stopper to test tube reaction of vinegar and baking soda proved:

  31. 9. Br2(l)+ heat Br2(g) • a. Br2(g)is added: reactants • b. Heat is added: products • c. Br2(g) is removed: products • d. Pressure is decreased: products • e. Temp decreased: reactants • 10. Lab18.1 Alka-seltzer reaction rates: • 1. Hot, cold and room temp water affected the rate of reaction, proved: • 2. Whole, broken, and powdered tablets affected the rate of reaction, • proved: • 3. Cork stopper to test tube reaction of vinegar and baking soda proved:

  32. 9. Br2(l)+ heat Br2(g) • a. Br2(g)is added: reactants • b. Heat is added: products • c. Br2(g) is removed: products • d. Pressure is decreased: products • e. Temp decreased: reactants • 10. Lab18.1 Alka-seltzer reaction rates: • 1. Hot, cold and room temp water affected the rate of reaction, proved: • Higher temp = faster rate • 2. Whole, broken, and powdered tablets affected the rate of reaction, • proved: more surface area = faster rate • 3. Cork stopper to test tube reaction of vinegar and baking soda proved: • if products have more moles of gas, the cork • creates greater pressure = slower rate

  33. Ch18 HW#2 7 – 9 • 7.Can a pressure change be used to shift equilibrium every reversible reaction? • HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) + heat • 8. Affect equilibrium: C(s) + H2O(g) + heat CO(g) + H2(g) • a) lower temp • b) Increase pressure • c) Remove H2 • d) Add H2O • e) Catalyst • f) Raise temp and decrease pressure • 9. Affect equilibrium: 2SO3(g) + CO2(g) + heat CS2(g) + 4O2(g) • a) Add CO2 • b) Add heat • c) Decrease pressure • d)Remove O2 • e) Add catalyst

  34. Ch18 HW#2 7 – 9 • 7.Can a pressure change be used to shift equilibrium every reversible reaction? • HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) + heat • Not when there are no gases present, or equal numbers. • 8. Affect equilibrium: C(s) + H2O(g) + heat CO(g) + H2(g) • a) lower temp • b) Increase pressure • c) Remove H2 • d) Add H2O • e) Catalyst • f) Raise temp and decrease pressure • 9. Affect equilibrium: 2SO3(g) + CO2(g) + heat CS2(g) + 4O2(g) • a) Add CO2 • b) Add heat • c) Decrease pressure • d)Remove O2 • e) Add catalyst

  35. Ch18 HW#2 7 – 9 • 7.Can a pressure change be used to shift equilibrium every reversible reaction? • HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) + heat • Not when there are no gases present, or equal numbers. • 8. Affect equilibrium: C(s) + H2O(g) + heat CO(g) + H2(g) • a) lower temp Reactants • b) Increase pressure Reactants • c) Remove H2 Products • d) Add H2O • e) Catalyst • f) Raise temp and decrease pressure • 9. Affect equilibrium: 2SO3(g) + CO2(g) + heat CS2(g) + 4O2(g) • a) Add CO2 • b) Add heat • c) Decrease pressure • d)Remove O2 • e) Add catalyst

  36. Ch18 HW#2 7 – 9 • 7.Can a pressure change be used to shift equilibrium every reversible reaction? • HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) + heat • Not when there are no gases present, or equal numbers. • 8. Affect equilibrium: C(s) + H2O(g) + heat CO(g) + H2(g) • a) lower temp Reactants • b) Increase pressure Reactants • c) Remove H2 Products • d) Add H2O Products • e) Catalyst No Change • f) Raise temp and decrease pressure Both favor products • 9. Affect equilibrium: 2SO3(g) + CO2(g) + heat CS2(g) + 4O2(g) • a) Add CO2 • b) Add heat • c) Decrease pressure • d)Remove O2 • e) Add catalyst

  37. Ch18 HW#2 7 – 9 • 7.Can a pressure change be used to shift equilibrium every reversible reaction? • HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) + heat • Not when there are no gases present, or equal numbers. • 8. Affect equilibrium: C(s) + H2O(g) + heat CO(g) + H2(g) • a) lower temp Reactants • b) Increase pressure Reactants • c) Remove H2 Products • d) Add H2O Products • e) Catalyst No Change • f) Raise temp and decrease pressure Both favor products • 9. Affect equilibrium: 2SO3(g) + CO2(g) + heat CS2(g) + 4O2(g) • a) Add CO2 Products • b) Add heat Products • c) Decrease pressure Products • d)Remove O2 • e) Add catalyst

  38. Ch18 HW#2 7 – 9 • 7.Can a pressure change be used to shift equilibrium every reversible reaction? • HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) + heat • Not when there are no gases present, or equal numbers. • 8. Affect equilibrium: C(s) + H2O(g) + heat CO(g) + H2(g) • a) lower temp Reactants • b) Increase pressure Reactants • c) Remove H2 Products • d) Add H2O Products • e) Catalyst No Change • f) Raise temp and decrease pressure Both favor products • 9. Affect equilibrium: 2SO3(g) + CO2(g) + heat CS2(g) + 4O2(g) • a) Add CO2 Products • b) Add heat Products • c) Decrease pressure Products • d)Remove O2 Products • e) Add catalyst No Change

  39. Ch18.3 – Spontaneous Reactions • 2 things contribute to deciding if a reaction will proceed on its own: • Free Energy & Entropy • Free Energy – energy released from reactions • Gasoline(g) + O2(g) CO2(g) + H2O(g) + heat • can do work

  40. Exothermic reactions are usually spontaneous Endothermic reactions are usually non spontaneous - they can be spontaneous if the amount of disorder created has a bigger affect than the increase in energy Entropy (S) – a measure of the amount of disorder in a system. Natural processes head toward disorder Natural processes: Energy: High energy  low energy These will oppose each other. Entropy: Order  Disorder One will beat the other Most Least order order Solids ↔ Liquids ↔ Gases Least Most energy energy

  41. Ex) Are the following reactions spontaneous? Predict a) H2O(l) → H2O(g) b) C(s) + O2(g) → CO2(g) + 393.5 kJ

  42. Ex) Are the following reactions spontaneous? Predict a) H2O(l) → H2O(g) more order → more disorder less energy ← more energy b) C(s) + O2(g) → CO2(g) + 393.5 kJ order disorder → disorder less E more E ← More E (wins) Ch18 HW#3 10 – 17

  43. Lab18.2 – Equilibrium - due in 2 days - Ch18 HW#3 due at beginning of period

  44. Ch18 HW#3 10 – 17 10) Where does “lost” free energy end up? 11) Does free energy that’s lost as waste heat ever serve a useful function? 12) What’s a spontaneous reaction? Ex from life? 13) Products in one spontaneous reactions are more ordered then reactants. Is the entropy change favorable or unfavorable? 14) Higher entropy: a) new pack playing cards or used cards b) sugar cube dissolved in water or cube? c) 1g salt crystal or 1g powdered. 15) Are all spontaneous reactions exothermic?

  45. 10) Where does “lost” free energy end up? waste heat energy 11) Does free energy that’s lost as waste heat ever serve a useful function? 12) What’s a spontaneous reaction? Ex from life? 13) Products in one spontaneous reactions are more ordered then reactants. Is the entropy change favorable or unfavorable? 14) Higher entropy: a) new pack playing cards or used cards b) sugar cube dissolved in water or cube? c) 1g salt crystal or 1g powdered. 15) Are all spontaneous reactions exothermic?

  46. 10) Where does “lost” free energy end up? waste heat energy 11) Does free energy that’s lost as waste heat ever serve a useful function? Some heat energy can be converted into useful work 12) What’s a spontaneous reaction? Ex from life? 13) Products in one spontaneous reactions are more ordered then reactants. Is the entropy change favorable or unfavorable? 14) Higher entropy: a) new pack playing cards or used cards b) sugar cube dissolved in water or cube? c) 1g salt crystal or 1g powdered. 15) Are all spontaneous reactions exothermic?

  47. 10) Where does “lost” free energy end up? waste heat energy 11) Does free energy that’s lost as waste heat ever serve a useful function? Some heat energy can be converted into useful work 12) What’s a spontaneous reaction? Ex from life? A rxn that proceeds forward on its own Glucose and oxygen react to form carbon dioxide and water in your body 13) Products in one spontaneous reactions are more ordered then reactants. Is the entropy change favorable or unfavorable? reactants  products If this rxn is spontaneous less order more order order doesn’t support this! 14) Higher entropy: a) new pack playing cards or used cards b) sugar cube dissolved in water or cube? c) 1g salt crystal or 1g powdered. 15) Are all spontaneous reactions exothermic?

  48. 10) Where does “lost” free energy end up? waste heat energy 11) Does free energy that’s lost as waste heat ever serve a useful function? Some heat energy can be converted into useful work 12) What’s a spontaneous reaction? Ex from life? A rxn that proceeds forward on its own Glucose and oxygen react to form carbon dioxide and water in your body 13) Products in one spontaneous reactions are more ordered then reactants. Is the entropy change favorable or unfavorable? reactants  products If this rxn is spontaneous less order more order order doesn’t support this! Therefore entropy is unfavorable (This rxn MUST have a big energy change.) 14) Higher entropy: a) new pack playing cards or used cards b) sugar cube dissolved in water or cube? c) 1g salt crystal or 1g powdered. 15) Are all spontaneous reactions exothermic?

  49. 10) Where does “lost” free energy end up? waste heat energy 11) Does free energy that’s lost as waste heat ever serve a useful function? Some heat energy can be converted into useful work 12) What’s a spontaneous reaction? Ex from life? A rxn that proceeds forward on its own Glucose and oxygen react to form carbon dioxide and water in your body 13) Products in one spontaneous reactions are more ordered then reactants. Is the entropy change favorable or unfavorable? reactants  products If this rxn is spontaneous less order more order order doesn’t support this! Therefore entropy is unfavorable (This rxn MUST have a big energy change.) 14) Higher entropy: a) new pack playing cards or used cards Used b) sugar cube dissolved in water or cube? Dissolved c) 1g salt crystal or 1g powdered. Powder 15) Are all spontaneous reactions exothermic?

  50. 10) Where does “lost” free energy end up? waste heat energy 11) Does free energy that’s lost as waste heat ever serve a useful function? Some heat energy can be converted into useful work 12) What’s a spontaneous reaction? Ex from life? A rxn that proceeds forward on its own Glucose and oxygen react to form carbon dioxide and water in your body 13) Products in one spontaneous reactions are more ordered then reactants. Is the entropy change favorable or unfavorable? reactants  products If this rxn is spontaneous less order more order order doesn’t support this! Therefore entropy is unfavorable (This rxn MUST have a big energy change.) 14) Higher entropy: a) new pack playing cards or used cards Used b) sugar cube dissolved in water or cube? Dissolved c) 1g salt crystal or 1g powdered. Powder 15) Are all spontaneous reactions exothermic? Not always, an endothermic rxn can be spont if big increase in entropy.

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