Question

Work set 3 The rate of sucrose's decomposition is given as rate of sucrose decomposition = k[sucrose] If k = 0.21/hr and the initial concentration of sucrose is 0.010 M, determine how much time must pass for the concentration (M) of sucrose to decrease by 90.0%.

Answer 1

Answer:

Explanation:

A first-order reaction is a reaction that proceeds at a rate that depends linearly on only one reactant concentration.

We can Use the following First order kinetic equation for first-order reactions:

ln [A]t / [A]0 = - kt

where k= rate, t= time, [A]t= concentration after the elapsed time and [A]0 =initial concentration.

Step 1: Calculation of  the time (t)

Given initial concentration = [A]0 = 0.010 M K =0.21 /hr

time(t)= we need to find and concentration at time t = [A]t = [ 0.010 -  90% of 0.010 ] M = 0.001 M

So by using the first order kinetics equation

ln [A]t / [A]0 = - kt

=> ln [0.001] / [0.010 ] = -0.21 / hr × t

=> -2.302585093 = -t× 0.21 /hr

=> t= 10.965 hr