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Kinetic investigations of multistep organic reactions are crucial for fundamental mechanistic studieOrganic Chemistry Chemistry Question

Reaction progress kinetics

Kinetic investigations of multistep organic reactions are crucial for fundamental mechanistic studies and are also necessary for practical applications of organic synthesis.
... Let us define a parameter called [“excess”], which is equal to the difference in the initial concentrations of the two substrates:
[“excess”] =0 –0
Hence we can write: =0 ‒0 + = [“excess”] +

12.1.

Model Answer

r = k2

12.2.

Model Answer

tot = +

12.3.

Model Answer

Steady state approximation for 5: k‒1 + k2 = k1

12.4.

Show that the rate can now be written as:

where

and

For a given set of conditions, the valuestot and [“excess”] are constant, thus leaving

12.5.

Express the relationship between the heat flow dq(t) at a given time t evaluated during the period dt, the volume V of the reactor, the reaction enthalpy ΔrH and the rate r.

Model Answer

The rate of the reaction is expressed as r = 1 / V × (dn / dt) where dn is the amount of matter that has been transformed in the reaction with molar heat ΔrH during the time dt. Consequently, the heat flow during time dt is dq = dnΔrH = ΔrH V r dt.

12.6.

...has been considered.

Experiment A: [ArX]0 = 0.16 mol dm‒3 (mol L‒1 ) and 0 = 0.24 mol dm‒3
Experiment B: [ArX]0 = 0.12 mol dm‒3 and 0 = 0.20 mol dm‒3
For a given concentration [ArX] on the plot, which experiment yielded more product? (Experiment A / Experiment B)

Model Answer

...higher.

12.7.

Model Answer

Correct answer: Experiment A because if more product has been formed, it implies that more catalyst turnovers have been achieved.

12.8.

...observed for Experiment D, then catalyst deactivation is the factor responsible for the behavior shown on the figure above. (True / False)

Model Answer

Correct answer: True because in the case of product inhibition, the formation of the product would hamper the reaction and thus the more product the less efficient the deactivation is.

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