Key Concepts of Catalysts

Questions and Answers

What must happen before a chemical reaction can begin?

The concentration of reactant molecules must be reduced.

The concentrations of products and reactants must be equal.

The activation energy must be exceeded. (correct)

The activation energy must be reached. (correct)

Lactase and carbonic anhydrase are examples of what type of substance?

Enzyme (correct)

Product

Reactant

Substrate

Which statement best describes the amount of catalyst that remains at the end of a reaction?

The catalyst is consumed by the reaction, so none remains at the end of the reaction.

The amount of catalyst is the same at the end as at the beginning of the reaction. (correct)

Less catalyst is present at the end than at the beginning of the reaction.

More catalyst is present at the end than at the beginning of the reaction.

Which statement best describes how a catalyst can speed up a chemical reaction?

The catalyst decreases the activation energy needed. Signup and view all the answers

In a liquid volcano demonstration, what would be the catalyst?

The candy tablets being added to the drink. Signup and view all the answers

What do you call a substance that influences the reaction but does not participate in the reaction?

Catalyst Signup and view all the answers

What method would best answer the researcher's question about reaction rate and the effect of substance A?

First, measure how long it takes for the liquid to become clear if X and Y are mixed together. Then measure the time if substance A is added. Signup and view all the answers

Which two substances bind using a lock-and-key mechanism?

Enzyme and substrate Signup and view all the answers

Photosynthesis is an example of:

An endothermic reaction. Signup and view all the answers

How does a catalyst work?

By decreasing the activation energy of a reaction. Signup and view all the answers

Study Notes

Key Concepts of Catalysts

Activation energy must be exceeded for a chemical reaction to commence.
Catalysts, like lactase and carbonic anhydrase, are specialized substances known as enzymes, which facilitate chemical reactions without being consumed.

Catalyst Presence

The amount of catalyst remains unchanged after a reaction, indicating it is not consumed in the process.

Mechanisms of Catalysis

Catalysts accelerate reactions by lowering the activation energy required, making reactions occur faster.
Catalysts do not alter the concentrations of products or reactants directly; instead, they provide an alternative reaction pathway.

Practical Example

In a liquid volcano experiment, candy tablets act as a catalyst that initiates a vigorous reaction when added to a carbonated drink.

Definition of a Catalyst

A catalyst is a substance that influences but does not participate directly in the chemical reaction.

Experimental Design

To assess the impact of a substance (A) on the reaction rate between two liquids (X and Y), the best approach is to measure the time taken for the reaction to produce a clear liquid both with and without the presence of substance A.

Lock-and-Key Mechanism

This mechanism describes how enzymes bind specifically to substrates to facilitate reactions.

Photosynthesis

Photosynthesis is classified as an endothermic reaction, where energy is absorbed rather than released.

Functionality of Catalysts

Catalysts operate by decreasing the activation energy necessary for a reaction to proceed, thereby enhancing the reaction rate.

Description

This quiz explores the fundamental principles behind catalysts and their role in chemical reactions. Learn how catalysts like enzymes lower activation energy and enhance reaction rates while remaining unchanged. Test your understanding of catalysis with real-life examples and experimental designs.