Question

Review Constants Periodic T Part A The rate constant for a certain reaction is k=770x10-! If the initial reactant concentration was 0 250 M Express your answer with the appropriate units. what will the concentration be after 140 minutes? View Available Hint(s) Å RO- ? (A) - Value Units Submit Part B Azoro order reaction has a constant rate of 4 40x104 M/s. Ir after 40.0 seconds the concentration has dropped to 250x10-2M what was the initial concentration Express your answer with the appropriate units. ► View Available Hint(s)

Answer 1

Solution : - Part A :- Rate Constant, K=770x10 3 5 The unit of this rate constant (5) Suggst that it is a first order reaction. The intigrated rate law for first order reaction is given as - K= 2.303 log LA where [A].= initiallon enhatos SA] = Concentrations left . after timet given [A] = 0.250M - [A] =2 t= 14 menuts = 14x605 = 840 S 2-30 Patting rakus, 7.70 x103 = 2:30 og 0.250 As long = 7.70 410 x 540 ► longe en ons 2.8085 = D = 643.428 » [A] = 13.8858100 M

Part B :- for a gero order reactions, rate and rate Constants are the same. Rate or Rate estent k for a zero order reaction is given by K=[A]. - [A] where, (A) = Initial Concentratis . (A) = Concentrations luft - after timez en: Rate=k=u40x10" M2 {AJ. = 2 SAJ = 2.50x102 in t=40.05 .. unoxion = [A]. - 2.50x102 40 => [A]o = 40x440x10h + 2.50X10? » [Alo = 1.768102 +2.50X102 - [A] = 14.26x102 M