07:09Half-life of a second-order reaction | Kinetics | Chemistry | Khan AcademyKhan Academy Organic Chemistry494views
08:16Half-life of a first-order reaction | Kinetics | AP Chemistry | Khan AcademyKhan Academy Organic Chemistry611views
Multiple ChoiceDecomposition 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.553views1rank3comments
Multiple ChoiceRadioactive plutonium-239 (t1/2 = 2.41 × 105 yr) is used in nuclear reactors and atomic bombs. If there are 5.70 × 102 g of plutonium isotope in a small atomic bomb, how long will it take for the substance to decay to 3.00 × 102 g?1426views1rank1comments
Multiple ChoiceUse the data below to determine the half-life of decomposition of NOCl reaction which follows 2nd order kinetics.729views3comments
Multiple ChoiceThe conversion of methyl isonitrile into acetonitrile follows first-order kinetics with a half-life of 110.2 seconds. What mass of a 1.00-g sample of methyl isonitrile remains after 10.0 minutes? CH3 – N≡C → CH3 – C≡N339views
Multiple ChoiceWhat is the half-life of a second-order reaction in which 45.0% of the original concentration of 1.00 M remains after 325 seconds?349views
Textbook QuestionGiven the following diagrams at t = 0 min and t = 30 min After four half-life periods for a first-order reaction, what fraction of reactant remains? [Section 14.4]981views1rank1comments
Textbook QuestionConsider the first-order decomposition of A molecules (red spheres) in three vessels of equal volume. (1)-(3) (c) How will the rates and half-lives be affected if the volume of each vessel is decreased by a factor of 2?462views
Textbook QuestionConsider the first-order decomposition of A molecules (red spheres) in three vessels of equal volume. (1)-(3) (b) What are the relative half-lives of the reactions in vessels (1)–(3)?574views
Textbook Question(a) The gas-phase decomposition of SO2Cl2, SO2Cl21g2 ¡SO21g2 + Cl21g2, is first order in SO2Cl2. At 600 K the half-life for this process is 2.3 * 105 s. What is the rate constant at this temperature?1413views
Textbook QuestionConsider the first-order reaction AS B in which A molecules (red spheres) are converted to B molecules (blue spheres). (a) Given the pictures at t = 0 min and t = 1 min, draw pictures that show the number of A and B molecules present at t = 2 min and t = 3 min.756views
Textbook QuestionThe first-order rate constant for the decomposition of N2O5, 2 N2O51g2¡4 NO21g2 + O21g2, a t 70 C i s 6.82 * 10-3 s-1. Suppose we start with 0.0250 mol of N2O51g2 in a volume of 2.0 L. (c) What is the half-life of N2O5 at 70 C ?1042views
Textbook QuestionFrom the following data for the first-order gas-phase isomerization of CH3NC at 215 C, calculate the firstorder rate constant and half-life for the reaction: Time (s) Pressure CH3nC (torr) 0 502 2000 335 5000 180 8000 95.5 12,000 41.7 15,000 22.41179views
Textbook QuestionConsider the data presented in Exercise 14.19. (c) What is the half-life for the reaction?714views
Textbook QuestionThe decomposition of XY is second order in XY and has a rate constant of 7.02 * 10 - 3 M- 1 # s - 1 at a certain temperature. a. What is the half-life for this reaction at an initial concentration of 0.100 M?1683views
Textbook QuestionThe half-life for the radioactive decay of U-238 is 4.5 billion years and is independent of initial concentration. How long will it take for 10% of the U-238 atoms in a sample of U-238 to decay?4397views4rank1comments
Textbook QuestionThe half-life for the radioactive decay of U-238 is 4.5 billion years and is independent of initial concentration. If a sample of U-238 initially contained 1.5 * 1018 atoms when the universe was formed 13.8 billion years ago, how many U-238 atoms does it contain today?660views1rank
Textbook QuestionThe half-life for the radioactive decay of C-14 is 5730 years and is independent of the initial concentration. How long does it take for 25% of the C-14 atoms in a sample of C-14 to decay?1348views
Textbook QuestionThe half-life for the radioactive decay of C-14 is 5730 years and is independent of the initial concentration. If a sample of C-14 initially contains 1.5 mmol of C-14, how many millimoles are left after 2255 years?1749views
Textbook QuestionWhat is the half-life (in minutes) of the reaction in Problem 14.74 when the initial C4H6 concentration is 0.0200 M? How many minutes does it take for the concentration of C4H6 to drop from 0.0100 M to 0.0050 M?827views
Textbook QuestionThe tabulated data were collected for this reaction at 500 °C: CH3CN(g)¡CH3NC( g) Time (h) [Ch3Cn] (M) 0.0 1.000 5.0 0.794 10.0 0.631 15.0 0.501 20.0 0.398 25.0 0.316 b. What is the half-life for this reaction (at the initial concentration)?470views
Textbook QuestionTrans-cycloheptene 1C7H122, a strained cyclic hydrocarbon, converts to cis-cycloheptene at low temperatures. This molecular rearrangement is a second-order process with a rate constant of 0.030 M-1 s-1 at 60 °C. If the initial concentration of trans-cycloheptene is 0.035 M: (c) What is the half-life of trans-cycloheptene at an initial concentration of 0.075 M?343views
Textbook QuestionConsider two reactions. Reaction (1) has a constant halflife, whereas reaction (2) has a half-life that gets longer as the reaction proceeds. What can you conclude about the rate laws of these reactions from these observations?580views
Textbook QuestionThe desorption (leaving of the surface) of a single molecular layer of n-butane from a single crystal of aluminum oxide is found to be first order with a rate constant of 0.128>s at 150 K. a. What is the half-life of the desorption reaction?869views
Textbook QuestionThe desorption (leaving of the surface) of a single molecular layer of n-butane from a single crystal of aluminum oxide is found to be first order with a rate constant of 0.128>s at 150 K. b. If the surface is initially completely covered with n-butane at 150 K, how long will it take for 25% of the molecules to desorb (leave the surface)? For 50% to desorb?648views
Textbook QuestionThe evaporation of a 120-nm film of n-pentane from a single crystal of aluminum oxide is zero order with a rate constant of 1.92 * 1013 molecules>cm2 # s at 120 K. a. If the initial surface coverage is 8.9 * 1016 molecules>cm2, how long will it take for one-half of the film to evaporate?874views1rank
Textbook QuestionAmericium-241 is used in smoke detectors. It has a first-order rate constant for radioactive decay of k = 1.6 * 10-3 yr-1. By contrast, iodine-125, which is used to test for thyroid functioning, has a rate constant for radioactive decay of k = 0.011 day-1. (b) Which one decays at a faster rate?1028views
Textbook QuestionAmericium-241 is used in smoke detectors. It has a first-order rate constant for radioactive decay of k = 1.6 * 10-3 yr-1. By contrast, iodine-125, which is used to test for thyroid functioning, has a rate constant for radioactive decay of k = 0.011 day-1. (c) How much of a 1.00-mg sample of each isotope remains after three half-lives?1029views
Textbook QuestionThe rate of a first-order reaction is followed by spectroscopy, monitoring the absorbance of a colored reactant at 520 nm. The reaction occurs in a 1.00-cm sample cell, and the only colored species in the reaction has an extinction coefficient of 5.60 * 103 M-1 cm-1 at 520 nm. (c) Calculate the half-life of the reaction.361views
Textbook QuestionAnthropologists can estimate the age of a bone or other sample of organic matter by its carbon-14 content. The carbon-14 in a living organism is constant until the organism dies, after which carbon- 14 decays with first-order kinetics and a half-life of 5730 years. Suppose a bone from an ancient human contains 19.5% of the C-14 found in living organisms. How old is the bone?2711views
Textbook QuestionThe half-life for radioactive decay (a first-order process) of plutonium- 239 is 24,000 years. How many years does it take for one mole of this radioactive material to decay until just one atom remains?1386views
Textbook QuestionThe half-life for the first-order decomposition of N2O4 is 1.3 * 10-5 s. N2O41g2S 2 NO21g2 If N2O4 is introduced into an evacuated flask at a pressure of 17.0 mm Hg, how many seconds are required for the pressure of NO2 to reach 1.3 mm Hg?1169views
Open QuestionHow long will it take for the concentration of SO2Cl2 to decrease to 25% of its initial concentration?"342views
Open QuestionWhat is the rate constant of a first-order reaction when 20.0% of a reactant remains after 30.0 s?187views
Open QuestionWhat is the half-life for a particular reaction if the rate law is rate = (1301 min-1)[A]?189views