2:35 Wed, Oct 4The half-life of a reaction, t₁/2, is the time it takesfor the reactant concentration [A] to decrease byhalf. For example, after one half-life theconcentration falls from the initial concentration[A]o to [A]o/2, after a second half-life to [A]o/4,after a third half-life to [A]o/8, and so on. on.73%For a first-order reaction, the half-life is constant. It depends only on the rate constant k and not on the reactant concentration. It isexpressed asCPart AFor a second-order reaction, the half-life depends on the rate constant and the concentration of the reactant and so is expressedasValueSubmitμÅPart B-1SA certain first-order reaction (A-products) has a rate constant of 6.30×10-3 s-¹ at 45 °C. How long does it take for theconcentration of the reactant, [A], to drop to 6.25% of the original concentration?Express your answer with the appropriate units.► View Available Hint(s)μAUnitsValuet1/2?Units-In (2)kA certain second-order reaction (B→products) has a rate constant of 1.35×10-3 M-¹.s¹ at 27°C and an initial half-life of240 s. What is the concentration of the reactant B after one half-life?Express your answer with the appropriate units.► View Available Hint(s)?1t₁/2 =k[A]o|||<

Answer:Time required to take the concentration of reactant to half of its initial value is called as…

The half-life of a reaction, f/2, is the time it takes for the reactant concentration [A] to decrease by half. For example, after one half-life the concentration falls from the initial concentration [A]o to [A]o/2, after a second half-life to [A]o/4. after a third half-life to [A]o/8, and so on. on. For a first-order reaction, the half-life is constant. It depends only on the rate constant k and not on the reactant concentration. It is expressed as In(2) t1/2 = For a second-order reaction, the half-life depends on the rate constant and the concentration of the reactant and so is expressed as Part A A certain first-order reaction (A-products) has a rate constant of 6.30x10 3¹ at 45°C. How long does it take for the concentration of the reactant, [A], to drop to 6.25% of the original concentration? Express your answer with the appropriate units. ▸ View Available Hint(s) Value Submit HÅ ▾ Part B 1 Value Units 1 ? A certain second-order reaction (B-products) has a rate constant of 1.35x10-3 M-sat 27 °C and an initial half-life of 240 s. What is the concentration of the reactant B after one half-life? Express your answer with the appropriate units. View Available Hint(s) Units t1/2 = WA ?

The half-life of a reaction, f/2, is the time it takes for the reactant concentration [A] to decrease by half. For example, after one half-life the concentration falls from the initial concentration [A]o to [A]o/2, after a second half-life to [A]o/4. after a third half-life to [A]o/8, and so on. on. For a first-order reaction, the half-life is constant. It depends only on the rate constant k and not on the reactant concentration. It is expressed as In(2) t1/2 = For a second-order reaction, the half-life depends on the rate constant and the concentration of the reactant and so is expressed as Part A A certain first-order reaction (A-products) has a rate constant of 6.30x10 3¹ at 45°C. How long does it take for the concentration of the reactant, [A], to drop to 6.25% of the original concentration? Express your answer with the appropriate units. ▸ View Available Hint(s) Value Submit HÅ ▾ Part B 1 Value Units 1 ? A certain second-order reaction (B-products) has a rate constant of 1.35x10-3 M-sat 27 °C and an initial half-life of 240 s. What is the concentration of the reactant B after one half-life? Express your answer with the appropriate units. View Available Hint(s) Units t1/2 = WA ?

Chemistry: An Atoms First Approach

2nd Edition

ISBN:9781305079243

Author:Steven S. Zumdahl, Susan A. Zumdahl

Publisher:Steven S. Zumdahl, Susan A. Zumdahl

Chapter11: Chemical Kinetics

Section: Chapter Questions

Problem 5ALQ: Consider the following statements: In general, the rate of a chemical reaction increases a bit at...

See similar textbooks

Similar questions

Derive expressions for the half-life of zero-, first-, and second-order reactions using the integrated rate law for each order. How does each half-life depend on concentration? If the half- life for a reaction is 20. seconds, what would be the second half-Life assuming the reaction is either zero, first, or second order?
The label on a bottle of 3% (by volume) hydrogen peroxide, H2O2, purchased at a grocery store, states that the solution should be stored in a cool, dark place. H2O2decomposes slowly over time, and the rate of decomposition increases with an increase in temperature and in the presence of light. However, the rate of decomposition increases dramatically if a small amount of powdered MnO- is added to the solution. The decomposition products are H2O and O2. MnO2 is not consumed in the reaction. Write the equation for the decomposition of H2O2. What role does MnO2 play? In the chemistry lab, a student substituted a chunk of MnO2 for the powdered compound. The reaction rate was not appreciably increased. WTiat is one possible explanation for this observation? Is MnO2 part of the stoichiometry of the decomposition of H2O2?
When formic acid is heated, it decomposes to hydrogen and carbon dioxide in a first-order decay. HCOOH(g) CO2(g) + H2(g) At 550 C, the half-life of formic acid is 24.5 minutes. (a) What is the rate constant, and what are its units? (b) How many seconds are needed for formic acid, initially 0.15 M, to decrease to 0.015 M?
A substance undergoes first-order decomposition. After 40.0 min at 500°C, only 12.5% of the original sample remains. YYliat is the half-life of the decomposition? If the original sample weighed 243 g, how much would remain after 2.00 h?
The half-life of tritium, 3H, is 12.26 years. Tritium is the radioactive isotope of hydrogen. (a) What is the rate constant for the radioactive decay of tritium, in y1 and s1? (b) What percentage of the original tritium is left after 61.3 years?
The following rate constants were obtained in an experiment in which the decomposition of gaseous N2O; was studied as a function of temperature. The products were NO, and NO,. Temperature (K) 3.5 x 10_i 298 2.2 x 10"4 308 6.8 X IO-4 318 3.1 x 10 1 328 Determine Etfor this reaction in kj/mol.
Define stability from both a kinetic and thermodynamic perspective. Give examples to show the differences in these concepts.
A catalyst reduces the activation energy of a reaction from 215 to 206 kJ. By what factor would you expect the reaction-rate constant to increase at 25 C? Assume that the pre-exponential term (A) is the same for both reactions. (Hint: Use the formula ln k = ln A Ea/RT.)
Both technetium-99 and thallium-201 are used to image heart muscle in patients with suspected heart problems. The half-lives are 6 h and 73 h, respectively. What percent of the radioactivity would remain for each of the isotopes after 2 days (48 h)?
Consider the following statements: In general, the rate of a chemical reaction increases a bit at first because it takes a while for the reaction to get warmed up. After that, however, the rate of the reaction decreases because its rate is dependent on the concentrations of the reactants, and these are decreasing. Indicate everything that is correct in these statements, and indicate everything that is incorrect. Correct the incorrect statements and explain.
The compound Xe(CF3)2 decomposes in a first-order reaction to elemental Xe with a half-life of 30. minutes. If you place 7.50 mg of Xe(CF3)2 in a flask, how long must you wait until only 0.25 mg of Xe(CF3)2 remains?
There are two molecules with the formula C3H6 Propane, CH3CH = CH2, is the monomer of the polymer polypropylene, which is used for indoor-outdoor carpets. Cyclopropane is used as an anesthetic: When heated to 499 C, cyclopropane rearranges (isomerizes) and forms propane with a rate constant of 5.95104s1. What is the half-life of this reaction? What fraction of the cyclopropane remains after 0.75 h at 499 C?