IB Chemistry Topic R2.2.5 Catalysts Revision Notes (SL/HL)

IB Chemistry Topic R2.2.5 Catalysts Revision Notes (SL/HL) | RevisionDojo

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How Catalysts Work: An Alternative Reaction Pathway with a Lower Activation Energy

Recall from R2.2.4 that the activation energy ($E_a$) is the minimum energy that colliding particles need in order to react.
A catalyst speeds up a reaction by providing an alternative pathway with a lower activation energy.
This means more particles now have enough energy to overcome the activation barrier, leading to a higher frequency of successful collisions.

Key Characteristics of Catalysts:

Not consumed: Catalysts participate in the reaction but are regenerated at the end, so they are not used up.
Do not alter equilibrium: A catalyst accelerates both the forward and reverse reactions equally, leaving the equilibrium position and the overall enthalpy change ($\Delta H$) unchanged.
Specificity: some catalysts are highly selective and speed up only one reaction or a small group of related reactions.

Tip

A catalyst lowers the activation energy but does not affect the energy levels of the reactants or products. It only changes the pathway.

Energy Profiles: Catalyzed vs. Uncatalyzed Reactions

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How Catalysts Work: An Alternative Reaction Pathway with a Lower Activation Energy

Recall from R2.2.4 that the activation energy ($E_a$) is the minimum energy that colliding particles need in order to react.
A catalyst speeds up a reaction by providing an alternative pathway with a lower activation energy.
This means more particles now have enough energy to overcome the activation barrier, leading to a higher frequency of successful collisions.

Key Characteristics of Catalysts:

Not consumed: Catalysts participate in the reaction but are regenerated at the end, so they are not used up.
Do not alter equilibrium: A catalyst accelerates both the forward and reverse reactions equally, leaving the equilibrium position and the overall enthalpy change ($\Delta H$) unchanged.
Specificity: some catalysts are highly selective and speed up only one reaction or a small group of related reactions.

Tip

A catalyst lowers the activation energy but does not affect the energy levels of the reactants or products. It only changes the pathway.

Energy Profiles: Catalyzed vs. Uncatalyzed Reactions

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Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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Structure 1. Models of the particulate nature of matter5 subtopics

Structure 2. Models of bonding and structure4 subtopics

Structure 3. Classification of matter2 subtopics

Reactivity 1. What drives chemical reactions?4 subtopics

Reactivity 2. How much, how fast and how far?3 subtopics

Reactivity 3. What are the mechanisms of chemical change?4 subtopics

IB Chemistry R2.2.5 Catalysts Notes

Structure 1. Models of the particulate nature of matter5 subtopics

Structure 2. Models of bonding and structure4 subtopics

Structure 3. Classification of matter2 subtopics

Reactivity 1. What drives chemical reactions?4 subtopics

Reactivity 2. How much, how fast and how far?3 subtopics

Reactivity 3. What are the mechanisms of chemical change?4 subtopics

How Catalysts Work: An Alternative Reaction Pathway with a Lower Activation Energy

Key Characteristics of Catalysts:

Energy Profiles: Catalyzed vs. Uncatalyzed Reactions

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

How Catalysts Work: An Alternative Reaction Pathway with a Lower Activation Energy

Key Characteristics of Catalysts:

Energy Profiles: Catalyzed vs. Uncatalyzed Reactions

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account