15. Chemical Kinetics

Half-Life

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What is the half-life of radon-220?
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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.
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For a first-order reaction, what percentage of the reactant has been consumed after one half-life has elapsed?
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In a first-order reaction, what fraction of the original reactant has been consumed after 4 half-lives?
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How much of a radioactive parent isotope will remain after three half-lives have passed?
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If a sample initially contains 1.0 × 10^{12} atoms of the cadmium isotope 109Cd, which has a half-life of 462 days, approximately how many atoms of 109Cd will remain after 924 days?
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Which of the following is the correct formula for calculating the age of a meteorite using half-life?
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A radioactive isotope decays such that after 24 hours, only 25% of the original sample remains. What is the half-life of this isotope?
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Which of the following best describes the possible range of half-lives for radioactive isotopes?
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If the initial concentration of NO2(g) is 0.050 M, what is the half-life of the reaction at 300°C given that the rate constant k is 0.54 M⁻¹s⁻¹?
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After 5 half-lives have passed for 87Rb, what percentage of daughter isotopes would be present?
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If the decay constant for element X is 6.931 yr^{-1}, what is its half-life?
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Iodine-131 has a half-life of 8.0 minutes. How many half-lives will pass in 120 minutes?
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Which statement accurately describes a half-life?
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The half-life of bromine-74 is 25 min. How much of a 4.0 mg sample remains after 75 min?
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