Multiple Choice
In the reaction 3 BrO-(aq) → BrO3-(aq) + 2 Br-(aq), a plot of 1/[BrO-] vs. time is linear with a slope of 0. What does this indicate about the order of the reaction with respect to BrO-?
15. Chemical Kinetics
Half-Life
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Decomposition of a certain substance Y at 45°C was found to be zero order. What is the half-life of substance Y if it took 15.5 minutes to decompose 67% of this substance? [Y]0 = 0.25 M.
A
0.058 min
B
0.029 min
C
12 min
D
23.5 min
Verified step by step guidance1
Understand that for a zero-order reaction, the rate of reaction is constant and does not depend on the concentration of the reactant. The rate law is expressed as: , where is the rate constant.
The integrated rate equation for a zero-order reaction is: , where is the concentration at time , and is the initial concentration.
To find the rate constant , use the information that 67% of the substance decomposed in 15.5 minutes. Calculate the remaining concentration: . Substitute this into the integrated rate equation to solve for .
The half-life for a zero-order reaction is given by the formula: . Use the calculated value of from the previous step to find the half-life.
Substitute the initial concentration and the calculated rate constant into the half-life formula to determine the half-life of substance Y.
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