Kinetics & Equilibrium Factors that Affect Rates Le Châtelier's Principle Equilibrium Expressions K eq and Q Misc. Q $100 Q $200 Q $300 Q $400 Q $500 Q $100 Q $200 Q $300 Q $400 Q $500 Final Jeopardy

Which of the following will NOT increase the rate of a reaction? A.Increased surface area of a solid reactant B.Decreased volume in which the rxn occurs C.Faster moving molecules with higher KE D.Decreased pressure on gaseous reactants $100 Answer from Factors that Affect Rates

D. Decreased pressure on gaseous reactants

$200 Question from Factors that Affect Rates Using the collision model, explain, in detail, HOW the concentration of a reactant affects the rate of a reaction?

$200 Answer from Factors that Affect Rates Higher concentration = greater # of collisions due to greater # of particles = faster rate of rxn

$300 Question from Factors that Affect Rates The minimum energy required for a reaction to begin is known as the _______.

$300 Answer from Factors that Affect Rates Activation Energy

$400 Question from Factors that Affect Rates For molecules to actually react, they must have “effective collisions”. What are the 2 requirements for a collision to be considered “effective”?

$400 Answer from Factors that Affect Rates 1)Molecules collide with correct orientation 2)Molecules collide with enough energy to break reactant bonds

$500 Question from Factors that Affect Rates List all of the following that are true regarding the addition of a catalyst to a chemical reaction? A)Rate of reaction decreases B)Rate of the reaction increases C)There are a greater # of effective collisions D)The activation energy increases E)The activation energy decrease F)Catalysts in the body are known as substrates

$500 Answer from Factors that Affect Rates B) Rate of reaction increases C) Increases # of effective collisions E) Lowers activation energy

$100 Question from Eq. Expressions What type of reactants and products are not included in equilibrium expressions?

$100 Answer from Eq. Expressions pure solids & pure liquids

$200 Question from Eq. Expressions Write the equilibrium expression for the following reaction: NH 4 NO 3 (s) N 2 O(g) + 2H 2 O(l)

$200 Answer from Eq. Expressions Kp = (P N2O )

$300 Question from Eq. Expressions Balance the following and write the Kc expression: HC 2 H 3 O 2 (aq) + H 2 O (l) ↔ > H 3 O + (aq) + C 2 H 3 O 2 ¯ (aq)

$300 Answer from Unit Conversions HC 2 H 3 O 2 (aq) + H 2 O (l) ↔ H 3 O + (aq) + C 2 H 3 O 2 ¯ (aq) Kc = [H 3 O + ][C 2 H 3 O 2 ¯ ] [HC 2 H 3 O 2 ]

$400 Question from Unit Conversions Balance the following and write the Kc expression: ___Pb 3 (PO 4 ) 2 (s) ↔ ___ Pb 2+ (aq) + ___ PO 4 3 ¯ (aq)

$400 Answer from Eq. Expressions Pb 3 (PO 4 ) 2 (s) ↔ 3 Pb 2+ (aq) + 2 PO 4 3 ¯ (aq) Kc = [Pb 2+ ] 3 [PO 4 3 ¯] 2

$500 Question from Eq. Expressions Balance the following and write the Kp expression: ___ NH 3 (g) + ___ O 2 (g) ↔ ___ H 2 O (g) + ___ NO (g)

$500 Answer from Eq. Expressions 4 NH 3 (g) + 5 O 2 (g) ↔ 6 H 2 O (g) + 4 NO (g) Kp = (P H2O ) 6 (P NO ] 4 (P NH3 ) 4 (P O2 ) 5

$100 Question Keq and Q When Q > K, the reaction must shift the the _____ (left/right) in order to form more _____ (reactants/procucts)

$100 Answer from Keq & Q When Q > K, the reaction must shift the LEFT in order to form more REACTANTS

$200 Question from Keq & Q In terms of Q, the reaction quotient, and K, the equilibrium constant, what is true when a reaction is in equilibrium?

$200 Answer from Keq & Q Q = equilibrium

$300 Question from Keq & Q 2 NOCl (g) 2 NO (g) + Cl 2 (g) Predict the direction the reaction will shift to achieve equilibrium if the concentration of NO = M; Cl 2 = 0.7 M; NOCl = M; given that the Kc = 2.4 x 10 -7,

$300 Answer from Keq & Q 2 NOCl (g) 2 NO (g) + Cl 2 (g) Q = [NO] 2 [Cl 2 ] = [0.095] 2 [0.7] [NOCl] 2 [0.067] 2 Q = 1.41 ….. Q >K …. Shift Left (form reactants to decrease Q)

$400 Question from Keq & Q 2 CO 2 (g) + H 2 O (g) 2 O 2 (g) + CH 2 CO (g) Predict the direction the reaction will shift to achieve equilibrium if the concentration of CO 2 = 0.03 M; H 2 O = M; O 2 = M; CH 2 CO = M given that the Kc = 6.1 x 10 8,

$400 Answer from Keq & Q 2 CO 2 (g) + H 2 O (g) 2 O 2 (g) + CH 2 CO (g) Q = [O 2 ] 2 [CH 2 CO] = [0.055] 2 [0.009] [CO 2 ] 2 [H 2 O] [0.03] 2 [0.011] Q = 250 ….. Q < K …. Shift Right (form products to increase Q)

$500 Question from Keq & Q N 2 (g) + 3 H 2 (g) 2 NH 3 (g) Determine the equilibrium constant, Kc, if the concentrations of the following are: N 2 = 4.4 x M H 2 = 1.2 x M NH 3 = 3.4 x M

$500 Answer from Keq & Q N 2 (g) + 3 H 2 (g) 2 NH 3 (g) Kc = [NH 3 ] 2 = [3.4 x ] 2 [N 2 ][H 2 ] [4.4 x ][1.2 x ] 3 Kc = 0.152

$100 Question from Le Châtelier's Principle 2 CO 2 (g) + H 2 O (g) 2 O 2 (g) + CH 2 CO (g) Increasing the concentration of O 2 will cause the equilibrium to shift in which direction?

$100 Answer from Le Châtelier's Principle left

$200 Question from Le Châtelier's Principle Pb 3 (PO 4 ) 2 (s) ↔ 3 Pb 2+ (aq) + 2 PO 4 3 ¯ (aq) Decreasing the volume of the reaction container will cause the equilibrium to shift in which direction?

$200 Answer from Le Châtelier's Principle No shift… no gases, so volume has no affect

$300 Question from Le Châtelier's Principle 2 NOCl (g) ↔ 2 NO (g) + Cl 2 (g) Increasing the pressure on the reaction will shift the equilibrium in which direction?

$300 Answer from Le Châtelier's Principle To the left … side w/fewest gas molecules

$400 Question from Specific Le Châtelier's Principle 4 NH 3 (g) + 5 O 2 (g) ↔ 6 H 2 O (g) + 4 NO (g) Increasing the volume of the reaction container will cause the reaction to shift in which direction?

$400 Answer from Le Châtelier's Principle Right

$500 Question from Le Châtelier's Principle 2 CO 2 (g) + H 2 O (g) ↔ 2 O 2 (g) + CH 2 CO (g) Δ H = kJ If the temperature of the container is decreased, which direction will the equilibrium shift?

$500 Answer from Le Châtelier's Principle 2 CO 2 (g) + H 2 O (g) + heat (endo) ↔ 2 O 2 (g) + CH 2 CO (g) Δ H = kJ Left

$100 Question from Misc. A reaction in equilibrium that “lies to the right” will favor the formation of A)reactants B) products

$100 Answer from Misc. B) products

$200 Question from Misc. When a reaction is in equilibrium, which of the following is NOT true? A)The rate of the forward and reverse rxns are equal B)The concentrations of reactant and products are constant C)The concentrations of reactants and products are equal D)The molecules of reactants and products are still moving and reacting

$200 Answer from Misc. C) The concentrations of reactants and products are equal …is not true

$300 Question from Misc. A reaction in equilibrium “lies to the left”. The equilibrium constant, K, will be… A)K > 1 B) K < 1 C) K = 1

$300 Answer from Misc. B) K < 1 Lies to left = favors reactants = very tiny K value K = [products] [reactants]

$400 Question from Misc. PCl 5 (g) + heat ⇔ PCl 3 (g) + Cl 2 (g) In order to maximize the production of Cl 2, what should be done to the above reaction? A)Decrease the concentration of PCl 5 B)Decrease the volume of the reaction container C)Increase the concentration of PCl 3 D) Increase the temperature

$400 Answer from Misc. D) Increase the temperature

$500 Question from Misc. 4 HCl (g) + O 2 (g) ⇔ 2 H 2 O (l) + 2 Cl 2 (g) ΔH = kJ Which of the following would result from cooling down the temperature of the above reaction? A)Increase in the quantity of H 2 O produced B)Increase in the quantity of HCl produced C)Equilibrium shifts to the left

$500 Answer from Misc. 4 HCl (g) + O 2 (g) ⇔ 2 H 2 O (l) + 2 Cl 2 (g) + heat Decrease temp = shift to the right A) Increase in the quantity of H 2 O produced

Final Jeopardy g

Final Jeopardy Answer Constant Pressure