Acetone is one of the most important solvents in organic chemistry. It is used t
ID: 485954 • Letter: A
Question
Acetone is one of the most important solvents in organic chemistry. It is used to dissolve everything from fats and waxes to airplane glue and nail polish. At high temperatures, it decomposes in a first-order process to methane and ketene (CH_2==C==O). At 600 degree C, the rate constant is 8.7 times 10^-3 s^-1. What is the half-life of the reaction? Give your answer in scientific notation. How long does it take for 36% of a sample of acetone to decompose? s How long does it take for 83% of a sample of acetone to decompose? Give your answer in scientific notation.Explanation / Answer
ln A = -kt + ln Ao
Ao = Initial concentration of reactant
A = concentration of reactant at time t
K = rate constant
T = time
Rate constant = 0.693 / t1/2
Question a
t1/2 = 0.693 / 8.7 x 10-3
t1/2 = 79.65 seconds
Quesiton b
ln A = -kt + ln Ao
ln 0.64 = -8.7 x 10-3 x t + ln 1
ln 0.64 = -8.7 x 10-3 t
-0.4462 = -8.7 x 10-3 t
t = 51.29 seconds
Question c
ln A = -kt + ln Ao
ln 0.17 = -8.7 x 10-3 x t + ln 1
ln 0.64 = -8.7 x 10-3 t
-1.771 = -8.7 x 10-3 t
t = 203.67 seconds