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The half-life of a first-order reaction is The Half-Life of a First-Order Reaction This plot shows the concentration of the reactant in a first-order reaction as a function of time and identifies a series of half-lives, intervals in which the reactant concentration decreases by a factor of 2.In a first-order reaction, every half-life is the same length of time. Calculate the half-life for the hydrolysis reaction under these conditions.What is the half-life for the reaction under these conditions?If a flask that originally contains 0.077 M ethyl chloride is heated at 650°C, what is the concentration of ethyl chloride after 4 half-lives?

Analysis of a sample of charcoal from a fire in one such site gave a The half-life of a reaction is the time required for the reactant concentration to decrease to one-half its initial value.Answer: 4.3 × 10 As you learned in Chapter 1 "Introduction to Chemistry", radioactivity, or radioactive decay, is the emission of a particle or a photon that results from the spontaneous decomposition of the unstable nucleus of an atom.The rate of radioactive decay is an intrinsic property of each radioactive isotope that is independent of the chemical and physical form of the radioactive isotope. In this section, we will describe radioactive decay rates and how half-lives can be used to monitor radioactive decay processes.Other methods, such as tree-ring dating, have been used to calibrate the dates obtained by radiocarbon dating, and all radiocarbon dates reported are now corrected for minor changes in the C content of samples of wood from his tools gave a decay rate of 8.0 dpm/g carbon. Given: isotope and final activity Asked for: elapsed time Strategy: A Use Equation 14.30 to calculate and the rate constant, solve Equation 14.32 to obtain the elapsed time.Solution: We know the initial activity from the isotope’s identity (15 dpm/g), the final activity (8.0 dpm/g), and the half-life, so we can use the integrated rate law for a first-order nuclear reaction (Equation 14.32) to calculate the elapsed time (the amount of time elapsed since the wood for the tools was cut and began to decay). Exercise It is believed that humans first arrived in the Western Hemisphere during the last Ice Age, presumably by traveling over an exposed land bridge between Siberia and Alaska.