Question

The initial rate of the reaction: BrO3- (aq) + 5Br-(aq) + 8H+(aq) 3Br2(l) + H2O(l) has been measured at the reaction concentrations shown in mol/L. Experiment[BrO3-][Br-][H+]Initial rate (mol/(L∙s)10.100.100.108.0 x 10-420.200.100.101.6 x 10-330.100.200.101.6 x 10-340.100.100.203.2 x 10-3Determine the order of reaction with respect to each reactant

Answer 1

To determine the order of the reaction with respect to each reactant, we must compare how the reaction rate changes when its concentration changes.

We have in experiment one the same concentration of reactants and a speed equal to 8.0x10^-4 mol/(L.s).

Now, in the second experiment, the concentration of BrO3 doubles, and the rest of the reagents remain the same. The speed is also doubled since 8.0x10^-4 x 2 = 1.6 x 10^-3.

The same happens with Br-, in the third experiment. The rate doubles as the Br concentration doubles.

So for these two reactants, the rate of reaction will be first-order, since as the concentration increases the rate increases in the same proportion.

Now, for H+ we have that by doubling the concentration the rate quadruples. This means that the reaction order is second order. When changing the concentration, the speed changes in order equal to 2

Answer:

the order of reaction will be:

Respect BrO3-: First order

Respect Br-: First order

Respect H+: Second order