(8 points) In a different experiment, it takes 15.00 minutes for the concentration of A to decrease by 28%. What was the initial concentration of A in this trial

Initial concentration = 2.30 M

Explanation:

Full Question;

For this question, consider the reaction A-->B with a rate constant k=7.17x10^-4 m/s.

From the units of the rate constant, we can tell that this is a Zero order reaction.

k = 7.17 x 10^-4 m/s

t = 15 minutes = 15 * 60 = 600s (Converting to seconds)

concentration of A to decrease by 28%.

[A] = Final Concentration

[A]o = Initial Concentration

[A] = [A]o - ( [A]o * 28 ) / 100

[A] = [A]o - 0.28[A]o

[A] = 0.72 [A]o

For a zero order reaction, we have;

[A] = [A]o -kt

Substituting the new value of [A], we have;

0.72 [A]o = [A]o - (7.17 x 10^-4 * 900)

0.28 [A]o = (7.17 x 10^-4 * 900)

[A]o = 2.30 M

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.