Consider the reaction: 2 N₂O( g) → 2 N₂(g) + O₂(g) a. Express the rate of the reaction in terms of the change in concentration of each of the reactants and products.

Video transcript

Welcome back everyone. To another video, consider the reaction, two moles of nitrogen dioxide, produce one mole of nitrogen gas and two moles of oxygen gas express the rate of the reaction in terms of the change in concentration of each of the reactants and products. So let's solve this classical problem. This is a very common problem where we simply once remember that whenever we want to express the weight of our reaction, we want to take into account our reactants and products. Sometimes if we're taking our reactant, we first will add a negative sign because the concentration is decreasing. On top of the fraction, we are using the change in concentration of that particular reactant. And in this case, it's the concentration of no two. Once again, the negative sign represents that the concentration is decreasing. So we are turning our negative value into a positive one on the bottom of our fraction. The first thing we want to include is the stoichiometry efficient, which is two in this case, and then adjacent to that coefficient we including delta T, which represents the change in time we perceive the same way. But now we're going to use a positive sign for each product. So we have positive change in the concentration of N two because the concentration of N two is increasing. And then we are dividing by the sty meric coefficient which is one. So we're not going to write it and then we're adding delta C on the bottom. And similarly, we have a positive change in the concentration of 02 because it's a product and its concentration is increasing. We're including the stoic merical vision of two just as we did for no two. And then delta T, in addition to that, sometimes we want to separate our stoic metrical efficients as fractions. So we can simply say that we have negative one half the change in concentration of NT divided by the change in time, we have separated that negative one half. And we are going to say that this must be equal to the change in the concentration of N two divided by the change in time, which is also equal to positive one half. The change in concentration of 02 divided by the change in time. We have got our final expression. We simply want to determine which one is the correct answer to us because we have ABC and D. So as we said, weight is equal to negative one half and 02 divided by delta T, right. So now what we can see is that we can eliminate options B and C. It can be a or D, right. So between A and D, let's see what's next A is incorrect because we have one half in front of NC. We don't have any one half in our expression. There's a coefficient of one, meaning the correct answer is option D and in this case, option D states that the rate can be expressed as negative one half multiplied by the change in the concentration of no two divided by the change in time, which is equal to the change in N two divided by the change in time, which is also equal to one half the change in 02 divided by the change in time. That would be it for today. And thank you for watching.