CHM2046 - Chemistry Fundamentals II: Chemical Kinetics

These flashcards cover key concepts related to chemical kinetics, focusing on catalysts, enzymatic processes, and their mechanisms.

What are catalysts and how do they affect chemical reactions?

Catalysts are substances that affect the rate of a reaction without being consumed, by providing an alternative mechanism with lower activation energy.

Describe the difference between homogeneous and heterogeneous catalysis.

Homogeneous catalysts are in the same phase as the reactants, whereas heterogeneous catalysts are in a different phase than the reactants.

What is the purpose of a catalytic converter in a car's exhaust system?

A catalytic converter helps eliminate pollutants in the exhaust by facilitating reactions that convert harmful gases into less harmful ones.

Explain the Lock and Key mechanism in enzyme-substrate binding.

In the Lock and Key mechanism, a substrate fits into the active site of an enzyme much like a key fits into a lock, forming an enzyme-substrate complex.

What is the significance of activation energy in catalysis?

Activation energy is the energy barrier that must be overcome for a reaction to proceed. Catalysts lower this activation energy, allowing reactions to occur more easily.

What is an enzyme and its role in biological reactions?

An enzyme is a protein molecule that catalyzes biological reactions, often by adsorbing the substrate onto an active site to orient it for reaction.

What happens to a catalyst during a reaction mechanism?

A catalyst may be consumed in an early mechanism step but is regenerated in a later step, allowing it to facilitate multiple reactions.

How is the energy profile for a catalyzed reaction different from an uncatalyzed reaction?

The energy profile for a catalyzed reaction shows a lower activation energy barrier compared to the uncatalyzed reaction.

Give an example of a heterogeneous catalyst.

A common example of a heterogeneous catalyst is the catalytic metal in a catalytic converter, which is in a different phase than the exhaust gases.

Describe the steps of enzymatic hydrolysis of sucrose.

The reaction proceeds as follows: 1) Enzyme + Substrate → Enzyme-Substrate complex; 2) Enzyme-Substrate complex → Enzyme + Product.