1643 In a firstorder decomposition 500 of a compound decomp

16.43.) In a first-order decomposition, 50.0 % of a compound decomposes in 10.5 min a. What is the rate constant for this reaction? Tutor/Prof Initials b. How long does it take for 75.0% of the compound to decompose?

Solution

t   = 10.5min = 10.5*60sec   = 630sec

K    = 2.303/t log[A0]/[A]

K    = 2.303/630 log100/50

K   = 0.00365*0.3010    = 0.0011sec^-1

b.

K = 2.303/t log[A0]/[A]

0.0011   = 2.303/t log100/75

0.0011   = 2.303*0.125/t

t          = 2.303*0.125/0.0011     = 261.7sec >>>>answer