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**Drill:**• List five factors & explain how each affect reaction rates**CHM II HW**• Review PP-19 & 20 • Complete the attached worksheet & turn it in tomorrow • Lab Thursday**Equilibrium**• The point at which the rate of a forward reaction = the rate of its reverse reaction**Equilibrium**• The concentration of all reactants & products become constant at equilibrium**Equilibrium**• Because concentrations become constant, equilibrium is sometimes called steady state**Equilibrium**• Reactions do not stop at equilibrium, forward & reverse reaction rates become equal**Reaction**• aA(aq)+ bB(aq) pP(aq)+ qQ(aq) • Ratef = kf[A]a[B]b • Rater = kr[P]p[Q]q • At equilibrium, Ratef = Rater • kf[A]a[B]b = kr[P]p[Q]q**At equilibrium, Ratef = Rater**kf[A]a[B]b = kr[P]p[Q]q kf /kr = ([P]p[Q]q)/ ( [A]a[B]b) kf /kr = Kc = Keq in terms of concentration Kc = ([P]p[Q]q)/ ( [A]a[B]b)**All Aqueous**aA + bB pP+ qQ**Equilibrium Expression**( Products)p (Reactants)r Keq=**Drill: Solve Rate Expr:**X + Y M + N fast 3M + N 2G fast 2N K fast 2G + K Prod. slow**Drill: Solve Rate Expr:**X + Y M + N fast 3M + N 2G fast 2N K fast 2G + K Prod. slow**Drill: Solve Rate Expr:**X + Y M + N fast 3M + N 2G fast 2N K fast 2G + K Prod. slow**Drill: Solve Rate Expr:**X + Y M + N fast 3M + N 2G fast 2N K fast 2G + K Prod. slow**Drill: Solve Rate Expr:**3X + 3Y 3M + 3N 3M + N 2G fast 2N K fast 2G + K Prod. slow**Solve Rate Law**A + B C + D fast 4 C + A 2G fast 2 K 4D + B fast G + K 2 Q + 2 W fast Q + W Prod. slow**Drill: Solve Rate Law**A + B C + D fast 4 C + A 2G fast 2 K 4D + B fast G + K 2 Q + 2 W fast Q + W Prod. slow**Drill: Solve Rate Law**A + B C + D fast 4 C + A 2G fast 4 D + B 2K fast G + K 2 Q + 2 W fast Q + W Prod. slow**Drill: Solve Rate Law**A + B C + D fast 4 C + A 2G fast 4 D + B 2K fast G/2 + K/2 Q + W fast Q + W Prod. slow**Reverse Rxn 3Divide Rxn 4 by 2 & cancelDivide Rxns 2 & 3 by**4 & cancel**Drill: Solve Rate Law**A + B C + D fast C + A/4 G/2 fast D + B/4 K/2 fast G/2 + K/2 Q + W fast Q + W Prod. slow**Reverse Rxn 3Divide Rxn 4 by 2 & cancelDivide Rxns 2 & 3 by**4 & cancelAdd the rxns**CHM II HW**• Review PP-19 & 20 • Remember M. S.**Equilibrium Applications**• When K >1, [P] > [R] • When K <1, [P] < [R]**Equilibrium Calculations**• Kp = Kc(RT)Dngas**Equilibrium Expression**• Reactants or products not in the same phase are not included in the equilibrium expression**Equilibrium Expression**aA(s)+ bB(aq) cC(aq)+ dD(aq) [C]c [D]d [B]b Keq=**Reaction Mechanism**• When one of the intermediates anywhere in a reaction mechanism is altered, all intermediates are affected**Reaction Mechanism**• 1) A + B <---> C + D • 2) C + D <---> E + K • 3) E + K <---> H + M • 4) H + M <----> P**Lab Results**• % 100 80 60 40 • RT 5.21 8.42 11.9 21.7 • WR 2.75 4.23 7.96 11.2**aA(aq) + bB(aq) pP(aq) + qQ(aq)**ReactionQuotient where [A], [B], [P], and [Q] are molarities at any time. Q = K only at equilibrium.**Drill: NH3 H2 + N2**At a certain temperature at equilibrium Pammonia = 4.0 Atm, Phydrogen = 2.0 Atm, & Pnitrogen = 5.0 Atm. Calculate Keq:**CHM II HW**• Review PP 19 & 20 • Complete the attached assignment & turn it in tomorrow**aA(aq) + bB(aq) pP(aq) + qQ(aq)**ReactionQuotient where [A], [B], [P], and [Q] are molarities at any time. Q = K only at equilibrium.**Equilibrium Applications**• When K > Q, the reaction goes forward • When K < Q, the reaction goes in reverse**Equilibrium Calculations**• aA + bB pP + qQ • Stoichiometry is used to calculate the theoretical yield in a one directional rxn**Equilibrium Calculations**• aA + bB pP + qQ • In equilibrium rxns, no reactant gets used up; so, calculations are different**Equilibrium Calculations**• Set & balance rxn • Assign amounts with x • Write eq expression • Substitute amounts • Solve for x