How long will it take for the concentration of A to decrease from 0.850 M to 0.205 for the reaction A → Products? (k = 0.0882 M⁻¹s⁻¹)

16.1 s

Explanation:

The reaction,  A → Products, follows first order kinetics.

So,

ln[A] = ln[A]o - kt

Where;

[A] = concentration at time= t

[A]o = initial concentration

k= rate constant

t = time taken

ln(0.205) = ln(0.850) - 0.0882t

ln(0.205) -  ln(0.850) = - 0.0882t

-1.5847 - (-0.1625) = - 0.0882t

-1.5847 + 0.1625 = - 0.0882t

-1.4222 = - 0.0882t

t = -1.4222/- 0.0882

t = 16.1 s

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year