Question

Specify which of the following species cannot be isolated in a reaction: activated complex, product, intermediate.

Short answer

The activated complex cannot be isolated.

Step-by-step solution

Understanding Key Terms

Before identifying which species cannot be isolated, we need to understand the definitions: An activated complex is a transitional structure that forms during a chemical reaction, representing the highest energy point along the reaction path. A product is a substance formed as a result of a chemical reaction. An intermediate is a species that is formed and consumed during the reaction but is not seen in the overall balanced equation.

Identifying Isolatable Species

Products are stable and can be isolated after a reaction completes since they are the final substances produced. Intermediates can sometimes be isolated if their lifetime is sufficiently long under certain conditions, allowing for experimental techniques to capture them before they further react.

Analyzing Activated Complex

The activated complex is highly unstable because it represents a peak on the energy diagram of a reaction. It exists momentarily as reactants are transformed into products and, due to its transient nature and extreme instability, it cannot be isolated in a reaction.

Conclusion Based on Analysis

Given the stability characteristics and roles of these species in chemical reactions, the activated complex cannot be isolated due to its ephemeral existence in the transformation process.

Key concepts

Intermediate

In chemical reactions, an intermediate is a temporary species that forms and disappears as the reaction progresses. It's not something you'd see listed in the final products of a reaction because it only exists for a short time between reactants and products.
Think of intermediates as the middle stages in a chain reaction. When a reaction occurs, it can be broken down into several steps where intermediates play a vital role by linking one step to the next:

• Intermediates are formed in one step and used up in another.
• They are often transient and may be challenging to detect.
• Their stability can vary; some are more stable than others and might be isolated under specific conditions, even if just briefly.

Scientists can sometimes trap intermediates, although it's not always easy. Special experimental techniques are used when intermediates have a longer lifetime, helping to explore the mechanism of reactions more deeply.

Product

When a chemical reaction reaches completion, the new substances that emerge are called products. Unlike intermediates or activated complexes, products are stable and can often be easily isolated or collected. Here's how products fit into chemical reactions:

• They are formed as the end result of a reaction.
• Products are generally represented in the overall balanced equation of a chemical reaction.
• Once the reaction is complete, products remain and can be isolated for further use or study.

Products essentially represent the new arrangements of atoms after the chemical bonds in the reactants have been broken and formed. They are what you would typically observe and measure after conducting an experiment. This stability is what allows scientists to study and utilize the products in practical applications.

Chemical Reaction

Chemical reactions are fundamental processes where substances, known as reactants, transform into different substances, known as products. This magical transformation is possible because of changes in atomic arrangements and bond energies:

• Reactants are the starting materials of a reaction.
• Products are the substances obtained after the reaction.
• The process involves breaking old chemical bonds in reactants and forming new ones in products.

During this transformation process, temporary species like the intermediate and activated complex may occur. Chemical reactions can be represented by chemical equations, which outline the substances involved and the changes they undergo. By understanding these reactions, we gain insight into the essential processes that govern the natural world, from biological systems to industrial applications.