Thermodynamic and Kinetic Control - AP Chemistry

What role does entropy change ( $\triangle S$ ) play in thermodynamics?

It affects Gibbs free energy. Entropy change contributes to overall $\Delta G$ calculation.
Identify which product is favored under thermodynamic control.

The product with the lower Gibbs free energy. Most negative $\Delta G$ indicates highest stability.
What does a negative $\triangle G$ indicate for a reaction?

The reaction is spontaneous. Negative $\Delta G$ means reaction proceeds forward spontaneously.
How does increasing temperature affect thermodynamic control?

It can increase thermodynamic control favorability. Higher T promotes equilibration toward stable products.
State the effect of a catalyst on reaction rate.

It increases the reaction rate. Lowers $E_a$ , increasing forward and reverse rates equally.
Which factor primarily determines kinetic control?

Activation energy. Height of energy barrier determines formation rate.
Identify the product formed when a reaction is under kinetic control.

The product formed at a faster rate. Pathway with lowest activation energy dominates formation.
Identify the type of control when the product is the most stable.

Thermodynamic control. Stability indicates thermodynamic favorability over kinetic.
Which factor primarily determines thermodynamic control?

Gibbs free energy. Overall energy change determines final product stability.
What is the difference between thermodynamic and kinetic control in a reaction?

Thermodynamic control favors stability; kinetic control favors speed. Thermodynamic focuses on lowest energy state, kinetic on pathway speed.
What is the activation energy barrier?

The energy required to initiate a reaction. Minimum energy needed for reactants to reach transition state.
What is the main characteristic of a thermodynamically controlled reaction?

Stability of the final product. Thermodynamic stability determines final product distribution.
What does the symbol $\triangle G$ represent?

Gibbs free energy change. Change in Gibbs free energy for the reaction.
Identify the product formed when a reaction is under thermodynamic control.

The most stable product. Product with most negative $\Delta G$ is thermodynamically favored.
Define kinetic control in one sentence.

Control based on the rate of product formation. Reaction outcome determined by formation rates, not stability.
What is the effect of a catalyst on the equilibrium position?

No effect on equilibrium position. Catalysts affect rate but not thermodynamic equilibrium.
In which condition is thermodynamic control more likely to dominate?

At higher temperatures. Higher T provides energy to overcome barriers, favoring stability.
What does the term 'activation energy' refer to?

The minimum energy needed to start a reaction. Energy barrier that must be overcome for reaction to proceed.
Define thermodynamic control in one sentence.

Control based on product stability. Reaction outcome determined by final energy states.
How does increasing temperature affect kinetic control?

It can decrease kinetic control favorability. Higher T allows equilibration, reducing kinetic preference.
What is the main characteristic of a kinetically controlled reaction?

Speed of product formation. Rate of formation determines which product predominates.
How does temperature affect thermodynamic versus kinetic control?

Higher T favors thermodynamic; lower T favors kinetic. Temperature affects energy available to overcome barriers.
In which condition is kinetic control more likely to dominate?

At lower temperatures. Lower T reduces thermal energy, favoring fastest pathway.
Find the term for a reaction that favors the fastest-formed product.

Kinetic control. Product with lowest $E_a$ forms fastest under kinetic control.
What outcome does high stability of a product suggest?

It is thermodynamically favorable. High stability corresponds to negative $\Delta G$ values.
Which control is associated with reaction reversibility?

Thermodynamic control. Reversible reactions can reach equilibrium, favoring stable products.
Choose the correct description for Gibbs free energy.

It indicates reaction spontaneity. Negative $\Delta G$ means spontaneous, positive means non-spontaneous.
What does a low activation energy imply for a reaction?

It is likely kinetically favorable. Low barrier means reaction proceeds quickly.
Which control is associated with reaction irreversibility?

Kinetic control. Irreversible reactions trap products, favoring fast formation.
Does kinetic control depend on reaction conditions?

Yes, especially temperature. Temperature strongly influences kinetic versus thermodynamic control.
What does a reaction under kinetic control prioritize?

It prioritizes the product formed fastest. Lowest activation energy pathway determines formation rate.
What is the role of a catalyst in kinetic control?

It lowers the activation energy. Provides alternative pathway with lower activation energy.
Identify the type of control when product formation is fast.

Kinetic control. Fast formation rate indicates kinetic control dominance.
What does a positive $\triangle G$ indicate for a reaction?

The reaction is non-spontaneous. Positive $\Delta G$ means reaction requires energy input.
Find the term for a reaction that favors the most stable product.

Thermodynamic control. Product with lowest $\Delta G$ is thermodynamically favored.
Identify which product is favored under kinetic control.

The product with the lower activation energy. Lower $E_a$ means faster formation rate.
What does a reaction under thermodynamic control prioritize?

It prioritizes the most stable product. Lowest Gibbs free energy determines thermodynamic favorability.
What is the primary factor in determining reaction spontaneity?

Gibbs free energy. Negative $\Delta G$ indicates spontaneous reaction direction.
State the formula for Gibbs free energy.

$\triangle G = \triangle H - T\triangle S$ . Combines enthalpy and entropy effects at given temperature.

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