19. a. The decomposition of a substance is first order. IF ittakes 5.8x 104s for the concentration of that substanceto fal lto falf its original value, what is the value of the rate,what is the value of the rate constant? b. The decomposition of anothe rsubstance is found to be firstorder. If k= 8.6 x 10 -6/s, what is the half life forthe reaction 19. a. The decomposition of a substance is first order. IF ittakes 5.8x 104s for the concentration of that substanceto fal lto falf its original value, what is the value of the rate,what is the value of the rate constant? b. The decomposition of anothe rsubstance is found to be firstorder. If k= 8.6 x 10 -6/s, what is the half life forthe reaction
Explanation / Answer
a ) Formula : ln [A]0 / [A] = kt Where t is the time kis the rate constant [A]concentration at time t [A]0 Initial concentration k = 1 / 5.8x104s ln ( x /x /2 ) = 0.693 / 5.8x 104s =0.11 * 10 ^ -4 s-1 = 1.1 * 10 ^ -5 s-1 b ) k = 8.6 x 10 -6/s t1/2 = 0.693 / 8.6 x10 -6/s = 0.0805 * 10 ^ 6 s b ) k = 8.6 x 10 -6/s t1/2 = 0.693 / 8.6 x10 -6/s = 0.0805 * 10 ^ 6 s