Some chemical reactions are affected by surface area, whereas others are not. Explain why this is so.

Wondering why you think reaction rate is not influenced by by surface area in some cases?

Idk it’s just a question I got and I don’t understand the unit at all lmao

Surface area can indeed affect the rate of a chemical reaction, but whether or not it has an impact depends on the nature of the reaction. To understand this, we need to consider the concept of reaction rate and the role of surface area.

The rate of a chemical reaction is determined by how quickly reactant particles collide and react with each other. Increasing the surface area of a reactant means exposing more of its particles to the other reactants, thus increasing the number of possible collisions. This, in turn, can lead to a faster reaction.

However, not all reactions are influenced by surface area. The extent to which surface area affects a reaction mainly depends on the reaction mechanism. One key factor is the availability of the reactive sites on the surface of the reactant. If the reaction involves a step where the reactant particles need to adsorb or bind to the surface in order to react, then increasing the surface area will increase the number of available sites for adsorption. As a result, the reaction rate may be significantly enhanced.

On the other hand, if the reaction mechanism does not involve adsorption or surface reactions, such as in many gas-phase reactions, then increasing the surface area might not have a significant effect on the reaction rate. In these cases, the reaction is primarily determined by the collision frequency and the energy of the reacting particles rather than the specific surface area.

In summary, surface area can influence the rate of a chemical reaction when the reaction mechanism involves adsorption or surface reactions. However, for reactions where the mechanism is primarily determined by collision frequency and energy, changes in surface area might have minimal impact. Understanding the reaction mechanism is essential to identify whether surface area is a significant factor in a specific chemical reaction.