Which of the following statements about reaction mechanisms is true?
Catalysts are not involved in elementary reactions.
Intermediates appear in the overall balanced equation.
The rate-determining step is always the last step in a mechanism.
The sum of the elementary steps must equal the overall balanced equation.
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For the elementary reaction A + B → C, what is the correct rate law?
Rate = k[A][B]
Rate = k[A] + k[B]
Rate = k[A]2 [B]
Rate = k[C] / ([A][B])
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How does an increase in temperature affect the Maxwell-Boltzmann distribution of molecular energies?
It narrows the distribution and shifts the peak to higher energies.
It widens the distribution and shifts the peak to lower energies.
It narrows the distribution and shifts the peak to lower energies.
It widens the distribution and shifts the peak to higher energies.
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According to the collision model, which of the following factors does NOT directly affect the rate of a chemical reaction?
Activation energy
Enthalpy change of the reaction
Frequency of collisions
Orientation of colliding molecules
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The Maxwell-Boltzmann distribution of the distribution of molecular energies in sample 1 of a gas is shown.
A change was made to the reaction conditions, as shown by the dotted curve, labelled sample 2.
What factor was changed in the reaction conditions to produce the dotted curve, labelled sample 2?
Temperature increased | Catalyst added | Volume reduced | |
|---|---|---|---|
A | X | X | ✓ |
B | X | X | X |
C | ✓ | X | X |
D | X | ✓ | X |
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