The effective rate constant for a gaseous reaction which has a Lindemann mechanism is 2.50 x 10-4 s-1 at 1.30 kPa and 2.10 x 10-5 s-1 at 12 Pa. Calculate the rate constant for the activation step in the mechanism.

10. The rate of change in colour of iodide (yellow) can be measured as it reacts with colourless hypochlorite, OCI (ag): I (aq) + OCI(aq) I0- (aq) + Cl (aq) a. Different concentrations of reactants are combined at the same temperature and the rate of yellow colour disappearance were measured: Rate of colour Trial Initial [I] (mol/L) Initial [OCI(ag)) change (mol/(L s) 0.12 0.18 7.91 x 102 1 0.18 3.95 x 102 0.060 0.090 0.030 9.88 x 103 3 0.24 7.91 x 102 4 0.090 Using the data provided, calculate the value of the rate constant, including units b. Predict the rate of reaction if both reactants have an equal starting concentration of 0.10 mol/1.

Suppose the reduction of nitric oxide proceeds by the following mechanism: step elementary reaction rate constant 1 H,(g) + 2 NO(g) → N,0(g) + H,0(g) k1 2 H2(9) + N,0(9) → N2(9) + H,O(g) Suppose also k, «k,. That is, the first step is much slower than the second. Write the balanced chemical equation for the overall chemical reaction: Write the experimentally- observable rate law for the overall chemical reaction. rate = k U Note: your answer should not contain the concentrations of any intermediates. Express the rate constant k for the overall chemical reaction in terms of k1, k2, and (if necessary) the rate constants k.1 and k-2 for k = the reverse of the two elementary reactions in the mechanism.

2C4H6(g) → C8H12(g) At high temperatures, the compound C4H6 (1,3-butadiene) reacts according to the equation above. The rate of the reaction was studied at 625 K in a rigid reaction vessel. Two different trials, each shown with a different starting concentration, were carried out. The data were plotted in three different ways, as shown below. (a) For trial 1, calculate the initial pressure, in atm, in the vessel at 625 K. Assume that initially all  the gas present in the vessel is C4H6. (Hint-this is a gas law problem from chemistry last year) (b) Use the data plotted in the graphs to determine the order of the reaction with respect to C4H6. (c) The initial rate of the reaction in trial 1 is 0.0010 mol/(L *s). Calculate the rate constant, k, for  the reaction at 625 K.