Question Video: Identifying Which Set of Conditions Gives the Greatest Rate of Reaction | Nagwa Question Video: Identifying Which Set of Conditions Gives the Greatest Rate of Reaction | Nagwa

# Question Video: Identifying Which Set of Conditions Gives the Greatest Rate of Reaction Science • Third Year of Preparatory School

## Join Nagwa Classes

In a series of experiments, a student changes both the concentration and the temperature. The conditions for each experiment are shown. In which conical flask is the rate of reaction likely to be highest?

03:10

### Video Transcript

In a series of experiments, a student changes both the concentration and the temperature. The conditions for each experiment are shown below. In which conical flask is the rate of reaction likely to be highest?

Rate of reaction measures how reactant or product concentration, mass, or volume changes over time. We can think of rate of reaction as the speed of a chemical reaction. To answer this question, we need to determine which flask will have the highest rate of reaction. In other words, we want to know which reaction is likely to be the fastest.

Let’s consider a chemical reaction between these two particles. Chemical reactions occur when particles successfully collide with one another. If we can increase the number of collisions between particles, then we can increase the rate of reaction. In the experiments, two conditions were changed: concentration and temperature.

Let’s first consider how changing the temperature might affect the number of collisions between particles. At this temperature, the particles have a certain amount of energy and are moving about, colliding with one another and the walls of the container. If we increase the temperature of this substance, the particles will gain energy and move faster. The faster the particles move, the more collisions they are likely to have. So increasing the temperature increases the number of collisions, which increases the rate of reaction.

Looking at the experiment conditions, we can see that two of the experiments were performed at 25 degrees Celsius and two were performed at 50 degrees Celsius. Since we need to determine which conical flask has the highest rate of reaction, and higher temperatures correspond to higher rates of reaction, we can eliminate options (A) and (D).

Now let’s consider how concentration might affect the number of collisions between particles. Concentration is the amount of a substance in a particular volume. For this example, we can think of the concentration as the number of particles in the box. Inside of the box, the particles are colliding with one another and the walls of the container. If we add more particles to the box, that is, we increase the concentration, there’s likely to be more collisions between the particles. Therefore, increasing the concentration increases the number of collisions, which increases the rate of reaction.

Looking at the two remaining answer choices, we see that conical flask (C) has a higher concentration than conical flask (B). As rate of reaction increases as the concentration increases, conical flask (C) should have a higher rate of reaction. Therefore, the conical flask that is likely to have the highest rate of reaction is flask (C) because this experiment was performed with the greatest concentration and at the highest temperature.

## 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