(a)
Interpretation:
A rough sketch of the energy profile for a reaction in which
Concept Introduction:
An energy profile is used to represent a single energetic pathway, containing the reaction coordinate, in which reactants are converted into products.
(b)
Interpretation:
A rough sketch of the energy profile for a reaction in which
Concept Introduction:
An energy profile is used to represent a single energetic pathway, containing the reaction coordinate, in which reactants are converted into products.
(c)
Interpretation:
A rough sketch of the energy profile for a reaction in which
Concept Introduction:
An energy profile is used to represent a single energetic pathway, containing the reaction coordinate, in which reactants are converted into products.
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Chemical Principles
- In the presence of excess thiocyanate ion, SCN, the following reaction is first order in iron(III) ion, Fe3+; the rate constant is 1.27/s. Fe3+(aq)+SCN(aq)Fe(SCN)2+(aq) What is the half-life in seconds? How many seconds would be required for the initial concentration of Fe3+ to decrease to each of the following values: 25.0% left, 12.5% left, 6.25% left, 3.125% left? What is the relationship between these times and the half-life?arrow_forwardIn the presence of excess thiocyanate ion, SCN, the following reaction is first order in chromium(III) ion, Cr3; the rate constant is 2.0 106/s. Cr3+(aq)+SCN(aq)Cr(SCN)2+(aq) What is the half-life in hours? How many hours would be required for the initial concentration of Cr3 to decrease to each of the following values: 25.0% left, 12.5% left, 6.25% left, 3.125% left?arrow_forward11.64 HBr is oxidized in the following reaction: 4 HBr(g) + O2(g) —• 2 H2O(g) + 2 Br,(g) A proposed mechanism is HBr + O2 -* HOOBr (slow) HOOBr + HBr — 2 HOBr (fast) HOBr + HBr — H2O + Bn (fast) Show that this mechanism can account for the correct stoichiometry. Identify all intermediates in this mechanism. What is the molecularity of each elementary’ step? Write the rate expression for each elementary' step. Identify the rate-determining step.arrow_forward
- The decomposition of iodoethane in the gas phase proceeds according to the following equation: C2H5I(g)C2H4(g)+HI(g) At 660. K, k = 7.2 104 sl; at 720. K, k = 1.7 102 sl. What is the value of the rate constant for this first-order decomposition at 325C? If the initial pressure of iodoethane is 894 torr at 245C, what is the pressure of iodoethane after three half-lives?arrow_forwardThe decomposition of NH3 to N2 and H2 was studied on two surfaces: Surface Ea (kJ/mol) W 163 Os 197 Without a catalyst, the activation energy is 335 kJ/mol. a. Which surface is the better heterogeneous catalyst for the decomposition of NH3? Why? b. How many times faster is the reaction at 298 K on the W surface compared with the reaction with no catalyst present? Assume that the frequency factor A is the same for each reaction. c. The decomposition reaction on the two surfaces obeys a rate law of the form Rate=k[NH3][H2] How can you explain the inverse dependence of the rate on the H2 concentration?arrow_forwardFor the reaction of iodine atoms with hydrogen molecules in the gas phase, these rate constants were obtained experimentally. 2I(g) + H2(g) 2HI(g) (a) Calculate the activation energy and frequency factor for this reaction. (b) Estimate the rate constant of the reaction at 400.0 K.arrow_forward
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