Given the reaction system;

2 NO (g) + O2 (g) -> 2 NO2 (g)

Write a brief explanation for each of the following statements in terms of the collision model and/or reactions mechanisms.

(1)Increasing the concentration of NO (g)makes the reaction go faster.

(2)Increasing the concentration of O2(g) has no effect on the reaction rate.

(3)Raising the temperature of the reaction mixture greatly increases the reaction rate.

When one increases the concn aren't more molecules provided to collide?

If increasing a reagent produces no change in the rate, that means it is zero order in that material.
If (3) is true, the reaction must be endothermic.

To understand each statement in terms of the collision model and/or reaction mechanisms, let's break them down one by one:

(1) Increasing the concentration of NO (g) makes the reaction go faster.

Explanation: According to the collision model, for a reaction to occur, reactant particles must collide with sufficient energy and correct orientation. The concentration of a gas is directly proportional to the number of gas particles present in a given volume. When you increase the concentration of NO (g), you increase the number of NO molecules available for collisions.

As a result, there will be an increase in the frequency of collisions between NO and O2, thus increasing the likelihood of successful collisions where reactants have enough energy and proper orientation to form the product NO2. Therefore, increasing the concentration of NO (g) makes the reaction go faster.

(2) Increasing the concentration of O2 (g) has no effect on the reaction rate.

Explanation: Similarly, increasing the concentration of O2 (g) would also increase the number of O2 molecules available for collisions. However, in this reaction, O2 acts as a reactant but does not affect the rate-determining step of the reaction.

The rate-determining step is the slowest step in a reaction mechanism that limits the overall rate of the reaction. In this case, increasing the concentration of O2 may increase the frequency of collisions but will not affect the rate-determining step because it does not directly participate in it.

Therefore, increasing the concentration of O2 (g) has no effect on the reaction rate.

(3) Raising the temperature of the reaction mixture greatly increases the reaction rate.

Explanation: The collision model explains that an increase in temperature results in an increase in the kinetic energy of particles. When the temperature is raised, the particles move faster, and the number of collisions between reactant molecules increases.

In addition to an increased collision frequency, raising the temperature also increases the average kinetic energy of the particles. This means more collisions have sufficient energy to overcome the activation energy barrier, resulting in a higher proportion of successful collisions and, therefore, a faster reaction rate.

So, raising the temperature of the reaction mixture greatly increases the reaction rate.