Question

A student mixes together the following amount of reactants and catalysts: 40.0mL of 2.0M acetone 30.0mL of 1.0M hydrochloric acid 20.0mL of 0.010M iodine 20.0mL of deionized water The mixture changes from a red colour to clear within 48 seconds

A. calculate the initial concentrations of the reactants and catalyst used in the experiment

B. calculate the reaction rate based upon the initial I2 concentration and the reaction time

Answer 1

moles of acetone = 2*40/1000= 0.08moles moles of hydrochloric acid = 1*30/1000=0.03 moles

moles of I2= 0.1*20/1000= 0.002 moles , volume of water= 20 ml

Total volume after mixing= 40+30+20+20= 110ml=110/1000= 0.11L

Concentrarions :acetone : 0.08/0.11=0.7272M Hydrochloriic acid = 0.03/0.11=0.2727M and I2= 0.002/0.11=0.018M

The reactin is iodinatino of acetone and HCl is the catalyst.( is supplies H+)

The reaction is zero order with respect to Acetone and all the iodine gets consumed. 0.018M of I2 requires 0.018 M of acetone.

acetone consumed =0.7272-0.018= 0.7092

-dc/dt= 0.7092/48= 0.015 M/s

for zero order -dc/dt= reaction rate