Question

question 7 (1 point)
why does an increase in concentration increase the rate of reaction?
collisions become more effective.
the number of collisions increases.
the activation energy decreases.
the average kinetic energy increases.
when there are more molecules in the container, they all speed up.

Explanation:

According to the collision theory, for a reaction to occur, reactant molecules must collide. When the concentration of reactants increases, there are more reactant molecules in a given volume. This leads to a higher frequency of collisions between the reactant molecules. More collisions mean a greater chance of effective collisions (those with proper orientation and sufficient energy), thus increasing the reaction rate.

• Collisions becoming more effective usually relates to factors like catalyst (which provides an alternative pathway with lower activation energy for effective collisions), not just concentration.
• Activation energy decrease is related to the presence of a catalyst, not concentration change.
• Average kinetic energy increase is related to temperature increase (as \(KE=\frac{3}{2}kT\), where \(k\) is Boltzmann constant and \(T\) is temperature), not concentration.
• Molecules speeding up is related to temperature (average kinetic energy is a measure of temperature for ideal gases, \(KE=\frac{1}{2}mv^{2}\) and \(T\propto KE\)), not just the number of molecules in a container (concentration).

Answer:

The number of collisions increases.