Question Video: Identifying Which Statement Regarding the Effect of Concentration on Rate of Reaction Is Correct | Nagwa Question Video: Identifying Which Statement Regarding the Effect of Concentration on Rate of Reaction Is Correct | Nagwa

Question Video: Identifying Which Statement Regarding the Effect of Concentration on Rate of Reaction Is Correct Science • Third Year of Preparatory School

Join Nagwa Classes

Attend live Science sessions on Nagwa Classes to learn more about this topic from an expert teacher!

Which of the following statements concerning the effect of concentration on the rate of reaction is correct? [A] Increasing the concentration increases the number of particles present; there is a greater number of collisions and so the rate of reaction decreases. [B] Increasing the concentration increases the number of particles present; there is a greater number of collisions and so the rate of reaction increases. [C] Increasing the concentration increases the number of particles present; there are fewer collisions and so the rate of reaction decreases. [D] Increasing the concentration decreases the number of particles present; there is a greater number of collisions and so the rate of reaction increases. [E] Increasing the concentration decreases the number of particles present; there are fewer collisions and so the rate of reaction decreases.

03:31

Video Transcript

Which of the following statements concerning the effect of concentration on the rate of reaction is correct? (A) Increasing the concentration increases the number of particles present; there is a greater number of collisions, and so the rate of reaction decreases. (B) Increasing the concentration increases the number of particles present; there is a greater number of collisions, and so the rate of reaction increases. (C) Increasing the concentration increases the number of particles present; there are fewer collisions, and so the rate of reaction decreases. (D) Increasing the concentration decreases the number of particles present; there is a greater number of collisions, and so the rate of reaction increases. (E) Increasing the concentration decreases the number of particles present; there are fewer collisions, and so the rate of reaction decreases.

Concentration is the amount of substance in a particular volume. Increasing the concentration means that there is more substance in the same volume, while decreasing the concentration means that there is less substance in the same volume.

If we look at the answer choices, we can see that answer choices (D) and (E) incorrectly describe increasing concentration as a decrease in the number of particles present. Let’s remove these incorrect answer choices so we can discuss how concentration affects the rate of reaction.

Rate of reaction measures how reactant or product concentration, mass, or volume changes over time. We can think of the rate of reaction as the speed of a chemical reaction. The rate of reaction is closely related to the number of collisions that occur between reactant particles per unit of time. In order for a reaction to take place, particles must successfully collide with the correct orientation and sufficient energy. If the number of collisions between reactant particles increases, then the chance of a successful collision will increase and the rate of reaction will increase.

To help us understand how concentration affects the rate of reaction, let’s consider two experiments involving the reaction between a metal and an acid. In one experiment, a low concentration of acid is used. And in the other experiment, a high concentration of acid is used. We know that the experiment using a high concentration of acid will have more acid particles per unit of volume than the experiment with a low concentration. The more particles present, the greater the number of collisions between the acid particles and the metal. And we know that as the number of collisions per second increases, the rate of reaction increases. So the reaction using a higher concentration of acid will be faster.

From our discussion, we now know that the statement concerning the effect of concentration on the rate of reaction that is correct is answer choice (B). Increasing the concentration increases the number of particles present; there is a greater number of collisions, and so the rate of reaction increases.

Join Nagwa Classes

Attend live sessions on Nagwa Classes to boost your learning with guidance and advice from an expert teacher!

• Interactive Sessions
• Chat & Messaging
• Realistic Exam Questions

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy