Kinetics Solutions: #7
7.* (1995 3 6) The reaction between bromate ions and bromide ions in acidic aqueous solution is BrO3-(aq) + 5Br- (aq) + 6H+ (aq) --> 3Br2(l) + 3H2O(l) Using the data from 4 experiments shown below determine the orders of the rate of reaction for all three reactants, the overall reaction order, and the value of the rate constant k.
Rate = k[BrO3-]a[Br-]b[H+]c Compare: Experiment 1 and 2 Double [BrO3-], rate doubles, so first order in [BrO3-], a = 1 Compare: Experiment 2 and 3 Double [Br-], rate doubles, so first order in [Br-], b = 1 Compare: Experiment 1 and 4 Double [H+], rate quadruples, so second order in [H+] Rate = k[BrO3-][Br-][H+]2 overall order = 1 + 1 + 2 = 4 To get k, simply plug in any value of the rate Experiment 1: rate = 8.0 X 10-4 M/s = k(0.10 M)(0.10 M)(0.10 M)2 k = 8.0 M-3s-1 Note: M is mole / L |