(d) Here is the experimental data for this reaction

Experiment # | Concentration[A] mol/L | Concentration[B] mol/L | Ratemol/litre-min |

1 | Constant | 1 | 4 |

2 | Constant | 3 | 12 |

3 | Constant | 5 | 20 |

4 | 2 | Constant | 3 |

5 | 4 | Constant | 12 |

6 | 6 | Constant | 27 |

Using the rate law data write the rate equation:Rate = k [A]^{2} [B]^{1}

What is the order? 3 . Why is the order different from the overall order?(From LMA)

The reaction does not occur in a single step. The reaction has a mechanism. The rate determining step shows that the reaction is a 3^{rd} order reaction.

What is the rate of the reaction in terms of B?

(e) When do the coefficients of the balanced overall equation equal to the exponents of the rate equation. When the exponents of LMA = the exponents of the RDS or if m and n are the exponents of the LMA and a and b are the exponents of the RDS When LMA = RDS or m = a and n = b

(f) The following mechanisms are proposed as possible mechanisms for the overall equation/ reaction. Show your evaluation of each mechanism briefly and summarize by acceptance or rejection of each mechanism with reasoning.

Mechanism | Evaluation – Your Reasoning |

(I) (1) A + B C (slow)(2) C + 2A D + E(fast)
(3) E F (fast) |
(1) 1 + 2 + 3 does not add up to give overall equation(2) RDS does not agree with the experiment
(3) Rate law, Rate = k[A] |

(II) (1) 2A + B 2E (slow)(2) 2E + A D + S (fast)
(3) S F (fast) |
(1) Elementary steps add up(2) RDS does agree with the experimentally determined rate law
ACCEPT the suggested mechanism |

(III) (1) 2A + B P (slow)(2) P + A = S + D (Fast)
(3) 2S F (fast) |
(1) The elementary steps does not add up to the overall equation(2) RDS does not agree with the experimentally determined rate law
REJECT the suggested mechanism |

(IV) (1) 2A + B D + G (slow)(2) G + A H (fast)
(3) H F (fast) |
(1) The elementary steps does add up(2) RDS does agree with the experimental evidence
ACCEPT the suggested mechanism |

(V) (1) 2A + B H + F (fast)(2) H + A D (slow) | (1) The elementary step does add up(2) The RDS does not agree with observed rate law
REJECT |

RDS = Rate determining step, LMA = Law of mass action

- (a) Heterogeneous catalysts is When the reactants and the catalyst are in different phases (states) then we have a heterogeneous catalyst. For example when Iron is used as a catalyst in the manufacture of ammonia in the Haber process. The promoter could be K
_{2}O, CaO or SiO_{2}

(a) Give examples with explanations of the catalysis of H_{2} + O_{2} to form H_{2}O or the decomposition of H_{2}O_{2} into water and oxygen. You have to find the catalysts

H_{2} + O_{2} H_{2}O . The catalyst for this reaction is Platinum or Pt

Decomposition of hydrogen peroxide is accelerated by MnO_{2}. Manganese dioxide is the catalyst.