Question

Half-life (kinetics) for First Order Reactions 19 of 32 > A Review | Constants Periodic Table The integrated rate law allows chemists to predict the reactant concentration after a certain amount of time, ar the time it would take for a certain concentration to be reached. The integrated rate law for a first-order reaction is: Half-life equation for first-order reactions: tn 12 = 0.02 where la is the half-life in seconds (s), and k is the rate constant in inverse seconds (8-). (A) = [Aloe- Now say we are particularly interested in the time it would take for the concentration to become one-half of its initial value. Then we could substitute for Al and rearrange the equation to: Part A 0.893 /2 = ? What is the half-life of a first-order reaction with a rate constant of 6.10x10 * Express your answer with the appropriate units. This equation calculates the time required for the reactant concentration to drop to half its initial value. In other words, it calculates the half-life. View Available Hint(s) TH HÅR O ? Value Units Submit Part B What is the rate constant of a first-order reaction that takes 385 seconds for the reactant concentration to drop to half of its initial value? Express your answer with the appropriate units. View Available Hint(s)
The integrated rate law allows chemists to predict the reactant concentration after a certain amount of time, or the time it would take for a certain concentration to be reached. The integrated rate law for a first-order reaction is: [A]=[A]0e−kt Now say we are particularly interested in the time it would take for the concentration to become one-half of its initial value. Then we could substitute [A]02 for [A] and rearrange the equation to: t1/2=0.693k This equation calculates the time required for the reactant concentration to drop to half its initial value. In other words, it calculates the half-life. Half-life equation for first-order reactions: t1/2=0.693k where t1/2 is the half-life in seconds (s), and k is the rate constant in inverse seconds (s−1). Part A What is the half-life of a first-order reaction with a rate constant of 6.10×10−4 s−1? Express your answer with the appropriate units. View Available Hint(s) nothing nothing Part B What is the rate constant of a first-order reaction that takes 385 seconds for the reactant concentration to drop to half of its initial value? Express your answer with the appropriate units. View Available Hint(s) nothing nothing Part C A certain first-order reaction has a rate constant of 6.20×10−3 s−1. How long will it take for the reactant concentration to drop to 18 of its initial value? Express your answer with the appropriate units. View Available Hint(s) nothing nothing Provide Feedback

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