A first-order decomposition reaction has a rate constant of 0.00140 yr−1. How long does it take for [reactant] to reach 12.5% of its original value? Be sure to report your answer to the correct number of significant figures.

Explanation:

rate constant k = .00140 yr⁻¹

k is rate constant , t is time taken for  decrease of initial concentration of a to a₁

Here a = 100 , a₁ = 12.5

.00140 = (1 / t )  x  ln 100 / 12.5

.00140 = 2.07944 / t

t = 1485.3 yr .

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.