2. 1. Define chemical or reaction kinetics:_____________________________ ___________________________________________________________ 2. Collision Theory: _____________________________________________ _____________________________________________________________ The more collisions, the _______________ the reaction. Two factors affecting the number of effective collisions a)_____________________ b)_____________________ The rate or speed of reactions speed rate time In order for chemicals to react, atoms or molecules must hit each other faster Sufficient speed Correct orientation + reactants products H 2 + Cl 2  2 HCl

3. According to the collision theory, why does each of the following usually increase the rate of reaction? a)Increase in temperature ____________________ __________________________________________ b) Increase in pressure for components in the gaseous phase. c) Increase in concentration _______________________ ______________________________________________ Push particles together, increases the concentration, they will hit more often Heating makes the particles move faster and therefore hit more often and harder (more effective) more particles in solutions, hit more often

4. e) Increase the surface area for reactions involving 2 phases _____________ ______________________________________________________________ f) Nature of reactants ____________________________________________ ______________________________________________________________ d) Addition of a catalyst _______________________________________ __________________________________________________________ powder it Speeds up a chemical reaction by lowering the activation energy Some chemicals (by their very nature), are more reactive than others More places for collisions to take place, like alkaseltzer & water Catalysts make an easier pathway for the reaction. They take part but are unchanged at the end of the reaction

5. Activated complex ___________________________________________Short lived temporary arrangement of atoms formed in the middle of a reaction + + or reaction coordinate beginning of reaction end of reaction

6. Potential Energy Diagrams: used to represent potential energy changes that take place as time progresses during chemical reactions A B C D E From the graph, label A-E next to the following : PE of reactants _____ PE of products ______ PE of activated complex ____ Activation energy _______ PEP-PER (PE products- PE reactants) ∆H Heat of reaction _______ A B C D E Reactants  products + energy H is Reaction feels HOT Exothermic: releases energy

8. Draw a diagram of an ENDOTHERMIC reaction and label the parts listed above Reaction coordinate (pathway) PE of reactants PE of products Heat of reaction ( H) activation energy PE of activated complex Potential energy reactants + energy  products H is + reaction feels COLD absorbs heat

9. What is most different about the 2 graphs of potential energy? ___________________________________________________ What is the sign (+/-) on heat of reaction for endothermic _________ exothermic __________ heat of reaction H and activation energy +

10. Summary endothermic cold + H absorbs energy exothermic hot - H releases energy Reactants + energy  products Reactants  products + energy

11. General rule: The more covalent bonds broken, the slower the reaction. Ionic bonded chemicals in water and transfers of electrons are faster. CATALYSTS On the 2 graphs above, draw a dotted line to show the pathway of a catalyzed reaction. What feature on the diagram for the catalyzed pathway should be most different from the regular graph? _______________________ Activation energy is lower, activated complex is lower Pb(NO 3 ) 2 (aq) + NaI (aq)  NaNO 3 (aq) + PbI 2 (s) CH 4 + 2 O 2  CO 2 + 2 H 2 O Mg +2 + Cu +1  Mg 0 + Cu +2 Ex Catalysts lower the hill slowest, strong,covalent bonds break fast, charges change transfer of e —’ s fast, ions in water

13. All reactions tend to lose heat energy: H (exothermic) and become more disordered: + S S is __________________________ H is __________________________ If these 2 conditions exist: -- H and + S there is a spontaneous reaction. Define spontaneous _____________________________________________ Entropy is name for disorder Enthalpy is name for heat energy A reaction that goes on by itself once it starts. (requires no input of energy).

14. ENTHALPY ENTROPY Reaction that release heat (joules) Phase changes become more disordered s  l  g or dissolving In reactions, increase # of moles is more disordered (Energy term is on the right side) Circle the reactions that have a -- H Circle the reactions that show a + S 1.Al (s) + 2070 joules  Al (l) 2.H 2 + I 2 + 12,000J  2 HI 3.He (g)  He (l) + 24 KJ 4.H 2 + Cl 2  2 HCl + 44,000J 5.H 2 S + 4,000J  H 2 + S 1.H 2 O (l)  H 2 O (g) 2.2H 2 (g) + O 2 (g)  2H 2 O (g) 3.MgCO 3 (s)  MgO (s) + CO 2 (g) 4.H 2 O (l)  H 2 O (s) 5.5. NaCl (s)  NaCl (aq)

15. ENTROPY cont 6. Raising the temperature of Al 7. Rain freezing 8. Dissolving sugar in water 9. A decomposition reaction 10. A synthesis reaction

17. Burning fuels (carbon compounds) combining with oxygen methane propane octane methanol & ethanol (alcohols) sugar (glucose)

18. HfHf Heat of formation salts in water (dissolving) disassociating into ions 2 elements  a compound

19. Reference Table I 1. Gives the heat of reactions for burning fuels ____________ forming compounds H f _____________ dissolving salts _______________ Stability of compounds: The most stable compounds are the most exothermic when formed - H (They would require the most energy to decompose.) Which are the 2 most stable compounds on Chart I? ______________ ______________ top 6 reactions middle bottom 6 (aq) on the product side Al 2 O 3 H2OH2O 2 elements  compoundH f is heat of formation Carbon cpds combining with oxygen Elements  compound + 2000 kJ To decompose must use that much E

20. Adjusting equations for 1 mole 1)2 H 2 (g) + O 2 (g)  2 H 2 O (g) How much is the H for 1 mole of water? Released or absorbed? H = _________ How much is the H for 1 mole of C 2 H 4 ? Released or absorbed? How much is the H for 1 mole of Al 2 O 3 ? Released or absorbed? 2) 4 Al (s) + 3 O 2 (g)  2 Al 2 O 3 (s) 3) N 2 (g) + O 2 (g)  2NO (g)H = _________ + 483.6 kJ- 483.6 kJ 1 H 2 (g) + ½ O 2 (g)  1 H 2 O (g) + 241.8 kJ 241.8 kJ released + 3351 kJ- 3351 kJ 2 Al (s) + 3 / 2 O 2 (g)  1 Al 2 O 3 (s)+1675.5 kJ 1675.5 kJ released + 182.6 kJ ½ N 2 (g) + ½ O 2 (g) + 91.3 kJ  1NO (g) + 182.6 kJ 91.3 kJ absorbed

21. 3 types of equilibrium Equilibrium: 1. Solution equilibrium Example: ___________________ Saturated solutions @ constant temperature KNO 3 (s) K + (aq) + NO 3 -- (aq) dissolving recrystallizing Gases: CO 2 (g) CO 2 (aq) (salts disassociate in H 2 O) State of balance between the rates of 2 opposite processes. It’s a dynamic system (it has not stopped) = or or equilibrium

22. 2. Phase equilibrium Example: _________________ melting = freezing evaporation = condensation H 2 O (s) H 2 O (l) H 2 O (l) H 2 O (g) @ 0 0 C or 273 K

23. Chemical equilbrium [ H 2 ] 4. Catalysts in chemical equilibrium _________________________ brackets mean concentration N 2 (g) + H 2 (g) NH 3 (g)making ammonia forward rate = backward rate Reaction appears to have stopped, but it’s NOT! Concentrations are constant, not equal. [N 2 ] + [H 2 ] = [NH 3 ] (not changing) No effect on equilibrium, just makes the reaction reach equilibrium FASTER! https://www.youtube.com/watch?v=wlD_ImYQAgQ https://www.youtube.com/watch?v=g5wNg_dKsYY

24. For a system at equilibrium – a reaction can be made to go more forward or backward in response to a stress. A new equilibrium is established. 1.Change in concentration A + B C + D Adding more C will shift _______ increasing _______ decreasing ______ A + B C + D Adding more A will shift _______ increasing _______ decreasing ______ A + B C + D Removing C, will shift _______ increasing _______ decreasing ______ left (toward reactants) right (toward the products) 2 steps: stress 1 st, then shift A & BD & C A & BD & C A & B

25. 2. Changes in pressure & volume AFFECTS GASES ONLY Increasing pressure or decreasing volume (the same thing) will shift _______________ Same # of molecule on both sides ________________ (s) And (l) in the equations ________________ A (g) + B (g) C (g) equilibrium to the side with the fewest molecules or moles No effect cross them out (g) + (l) 2 (g) + (s) 2 moles1 moles Shifts right (toward products)

26. 3. Changes in temperature Increasing temp. SHIFTS IN ENDOTHERMIC DIRECTION A + B C + D + energy - H ____________ A + B + energy C + D A + B C + D + energy A + B + energy C + D Opposite for cooling SHIFTS IN EXOTHERMIC DIRECTION (decreasing temp) + H ___________ 4. Common Ion Effect _________________________________ (dissolving a salt) Salts dissolved in H 2 O NaCl (s) Na + (aq) + Cl - (aq) Add a salt with a common ion like KCl Cl - + K + shifts left exothermic endothermic exo endo - H + H

27. 4. Common Ion Effect _________________________________ Salts dissolved in H 2 O NaCl (s) Na + (aq) + Cl -- (aq) Add a salt with a common ion like KCl Cl -- + K + shifts left

28. Equilibrium 1. Given the reaction: N 2 (g) + 3 H 2 (g) ↔ 2NH 3 (g) + 22.0 J When equilibrium is reached in this system, the rate of the forward reaction is (1) less than the rate of the reverse reaction (2) greater that the rate of the reverse reaction (3) equal to the rate of the reverse reaction (4) unrelated to the rate of the reverse reaction 2. Given the reaction system in a closed container at equilibrium and at a temperature of 298 K: N 2 O 4 (g) ↔ 2NO 2 (g) The measurable quantities of the gases at equilibrium must be (1) decreasing(3) equal (2) increasing(4) constant 3. A chemical reaction has reached equilibrium when (1) the reverse reaction begins (2) the forward reaction ceases (3) the concentration of the reactants and products become equal (4) the concentration of the reactants and products become constant 4. The diagram represents a sealed flask. Which equation represents a system that will reach equilibrium in the flask? (1) NaCl (s) ↔ NaCl (l)(3) H 2 O (g) ↔ NaCl (aq) (2) NaCl (s) ↔ H 2 O (l)(4) H 2 O (g) ↔ H 2 O (l)

29. 5. The diagram shows a bottle containing NH 3 (g) dissolved in water. How can the equilibrium: NH 3 (g) ↔ NH 3 (aq) be reached? (1) Add more water(3) cool the contents (2) Add more NH 3 (g) (4) stopper the bottle 6. The solid and liquid phases of water can exist in a state of equilibrium at 1 atm of pressure and a temperature of (1) 0 0 C(2) 100 0 C(3) 273 0 C(4) 373 0 C 7. Which description applies to a system in a sealed flask that is half full of water? (1) only evaporation occurs, but it eventually stops (2) only condensation occurs, but it eventually stops (3) neither evaporation nor condensation occurs (4) both evaporation and condensation occur 8. Which statement best describes a chemical reaction when it reaches equilibrium? (1) the concentrations of the reactants and products are the same (2) the concentrations of the reactants decrease to zero (3) the forward and reverse reaction rates are the same. (4) the forward reaction rate decreases to zero 9. As the number of effective collisions between reacting particles increases, the rate of reaction (1) increases(2) decreases(3) remains the same

30. LeChatelier’s Principle 1. In the equilibrium reaction: A(g) + 2B(g) + heat ↔ AB (g), the rate of the forward reaction will increase if there is (1) an increase in pressure (3) a decrease in temperature (2) an increase in the volume of the reaction vessel (4) a decrease in the concentration of A(g) 2. Given the reaction at equilibrium: N 2 (g) + 3 H 2 (g) ↔ 2NH 3 (g), if the pressure is increased at constant temperature, there will be an increase in the number of moles of (1) NH 3 (g) only(3) H 2 (g) only (2) N 2 (g) only(4) both N 2 (g) and H 2 (g) 3. Given the reaction at equilibrium: N 2 (g) + O 2 (g) = 2 NO(g), if the temperature remains constant and the pressure increases, the number of moles of NO (g) will (1) decrease(2) increase(3) remain the same

31. 4. Given the reaction at equilibrium: A(g) + B(g) ↔ AB (g) + heat, the concentration of A(g) can be increased by (1) lowering the temperature (3) increasing the concentration of AB(g) (2) adding a catalyst (4) increasing the concentration of B(g) 5. The addition of a catalyst to a system at equilibrium will increase the rate of (1) the forward reaction, only (3) both the forward and reverse reactions (2) the reverse reaction, only (4) neither the forward nor reverse reaction 6. Given the Haber reaction at equilibrium: N 2 (g) + 3 H 2 (g) ↔ 2NH 3 (g) + heat which stress on the system will decrease the production of NH 3 (g)? (1) increasing the concentration of N 2 (g)(3) decreasing the concentration of H 2 (g) (2) increasing the pressure on the system (4)decreasing the temperature on the system 7. Given the reaction at equilibrium: N 2 (g) + O 2 (g) ↔ 2 NO(g), as the concentration of N 2 (g) increases, the concentration of O 2 (g) will (1) decrease(2) increase(3) remain the same

32. 8. For a given system at equilibrium, lowering the temperature will always (1) increase the rate of reaction(3) favor the exothermic reaction (2) increase the concentration of products(4) favor the endothermic reaction 9. Given the equilibrium, system: 2A(g) + B(g) + 10 kJ ↔ C (g) Which conditions would yield the most product? (1) low temperature and high pressure(3) low temperature and low pressure (2) high temperature and high pressure(4) high temperature and low pressure 10. Given the reaction at equilibrium: N 2 (g) + 3 H 2 (g) ↔ 2NH 3 (g) + 22kJ Which stress would cause the equilibrium to shift to the left? (1) increasing the temperature(3) increasing the pressure (2) adding N 2 (g) to the system(4) adding H 2 (g) to the system 11. Given the reaction at equilibrium: C 2 (g) + D 2 (g) ↔ 2CD (g) + energy Which change will cause the equilibrium to shift? (1) increase in pressure(3) addition of heat (2) increase in volume(4) addition of a catalyst

33. H2OH2O ENTROPY AND ENTHALPY 1. At STP, a sample of which element has the highest entropy? (1) Na (s)(2) Hg (l)(3) Br (l)(4) F (g) 2. Systems in nature tend to undergo changes toward (1) lower energy and lower entropy (2) lower energy and higher entropy (3) higher energy and lower entropy (4) higher energy and higher entropy 3. Which sample has the lowest entropy? (1) 1 mole of KNO 3 (l)(3) 1 mole of KNO 3 (s) (2) 1 mole of H 2 O (l)(4) 1 mole of H 2 O (g) 4. As carbon dioxide sublimes, its entropy 5. Given the equation: KNO 3 (s) KNO 3 (aq), as H 2 O (l) is added to KNO 3 (s) to form KNO 3 (aq) the entropy of the system (1) increases(2) decreases(3) remains the same (1) increases(2) decreases(3) remains the same

34. 6. As the temperature of the system increases, the entropy of the system (1) increases(2) decreases(3) remains the same 7. As the reactants are converted to product in the reaction A(g) + B(g)  C(s), the entropy (1) increases(2) decreases(3) remains the same 8. Above 0 0 C, ice changes spontaneously to water according to the following equation: H 2 O (s) + heat  H 2 O (l). The changes in H 2 O (s) involve (1) an absorption of heat and a decrease in entropy (2) a release of heat and a decrease in entropy (3) an absorption of heat and an increase in entropy (4) a release of heat and an increase in entropy

35. The heat of reaction, ∆ H, is (1) negative and the reaction is spontaneous (2) negative and the reaction is not spontaneous (3) positive and the reaction is spontaneous (4) positive and the reaction is not spontaneous 10. Which reaction results in an increase in entropy? (1) CO 2 (g)  CO 2 (s) (2) H 2 O (l)  H 2 O (s) (3) Ca(s) + 2 H 2 O (l)  Ca(OH) 2 (aq) + H 2 (g) 4) NaCl(aq) + AgNO 3 (aq)  AgCl(s) + NaNO 3 (aq) 9. Given the reaction at 1 atm and 298 K: NaOH(s) Na + (aq) + OH - (aq) + 10.6kJ H2OH2O

36. Reference Table I 1. According to Ref Table I, when 2 moles of H 2 O (g) are formed from its element, (1) 484 kJ of heat is absorbed(3) 242 kJ of heat is absorbed (2) 484 kJ of heat is released(4) 242 kJ of heat is released 2. According to Ref Table I, which compound released the greatest amount of energy per mole when it is formed from its elements? (1) hydrogen iodide(3) ethyne (C 2 H 2 ) (2) carbon dioxide(4) ethene ( C 2 H 4 ) 3. According to Reference Table I, which statement best describes the formation of HI(g) ? (1) It is exothermic and heat is released. (2) It is exothermic and heat is absorbed. (3) It is endothermic and heat is released. (4) It is endothermic and heat is absorbed. 4. According to Table I, which salt releases energy as it dissolves? (1) KNO 3 (2) LiBr(3) NH 4 NO 3 (4) NaCl

37. 5. Given the reaction: CH 4 (g) + 2 O 2 (g)  2H 2 O (g) + CO 2 (g). what is the overall result when CH 4 (g) burns according to this reaction? (1) energy is absorbed and ∆ H is negative (2) energy is absorbed and ∆ H is positive (3) energy is released and ∆ H is negative (4) energy is released and ∆ H is positive 6. The heat of reaction (∆ H) is equal to the (1) heat content of the products minus the heat content of the reactants (2) heat content of the reactants minus the heat content of the products (3) heat content of the reactants divided by the heat content of the products (4) heat content of the products divided by the heat content of the reactants 7. Given the reaction: N 2 (g) + O 2 (g) + 182.6kJ  2 NO(g), what is the heat of formation of nitrogen (II) oxide in kJ/mole? (1) -182.6(2) -91.3(3) 182.6(4) 91.3 8. According to Reference Table I, the decomposition of which compound is exothermic? (1) ethane (C 2 H 6 ) (2) nitrogen (II) oxide (3) carbon dioxide (4) ammonia

38. 9. The reaction A (g) + B (g)  C (g) + D (g) + 30 kJ has a forward activation energy of 20 kJ. What is the activation energy for the reverse reaction? (1) 10 kJ(2) 20 kJ(3) 30 kJ(4) 50 kJ 10. Based on Reference Table I, when 2.00 mole of NaOH (s) dissolves in water (1) 44.5 kJ of energy is released and the temperature of the water increases (2) 44.5 kJ of energy is absorbed and the temperature of the water decreases (3) 89 kJ of energy is released and the temperature of the water increases (4) 89 kJ of energy is absorbed and the temperature of the water decreases