Question

question 10 (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, the rate of a chemical reaction depends on the frequency of effective collisions between reactant molecules. When the concentration of reactants increases, there are more molecules in the same volume. This leads to a higher number of collisions between reactant molecules. More collisions mean a higher chance of effective collisions (those with proper orientation and sufficient energy to overcome the activation energy barrier), thus increasing the reaction rate.

• Collisions becoming more effective is related to factors like orientation or activation energy (not directly concentration - this is more about catalyst or temperature in some orientation - related aspects).
• Activation energy decrease is typically due to a catalyst, not concentration.
• Average kinetic energy increase is due to temperature rise (as \(KE=\frac{3}{2}kT\), where \(k\) is Boltzmann constant and \(T\) is temperature).
• Molecules speeding up because there are more of them is not a valid scientific explanation. Molecular speed is related to temperature (\(v_{rms}=\sqrt{\frac{3RT}{M}}\) for gases, where \(R\) is gas constant, \(T\) is temperature, and \(M\) is molar mass) not just the number of molecules in a container.

Answer:

The number of collisions increases.