Imagine that the reaction 2 CO1g2 + O21g2¡2 CO21g2 occurs in a container that has a piston that moves to maintain a constant pressure when the reaction occurs at constant temperature. Which of the following statements describes how the volume of the container changes due to the reaction: (a) the volume increases by 50%, (b) the volume increases by 33%, (c) the volume remains constant, (d) the volume decreases by 33%, (e) the volume decreases by 50%.

Video transcript

Hey everyone in this example, we're given the following equation. We're told that it occurs in a vessel with a piston to ensure constant pressure and temperature. And we need to determine how the volume changes because of this reaction. So what we should recall is avocados law And we would recall that equal to the initial volume of our gas is divided by the initial moles of our gas is set equal to the final volume of our gasses and divided by the final number of moles of our gasses. So we would recognize that N1 is equal to the moles of our reactant And and two is equal to the M.nolds of our products. So looking at our equation given, we would count the moles of our reactant being one mole of carbon monoxide added to three moles of hydrogen gas for a total of four moles of our reactant side. Now, for our product side, we would count the one mole of methane gas added to the one mole of water in gaseous form. And that would give us two moles of our gaseous products. So what we can do is because this question wants us to determine how the volume changes. We're going to be solving for the final volume. So we would have V two or final volume equal to our initial volume of our gasses and then multiplied by the quotient where we're going to have our most of our react most of our products in the numerator and two divided by the moles of our reactant in the denominator and so we can We can substitute this so that we have V1 multiplied by the most of our products from our equation, that was two moles of our products divided by the molds of our reactant from our given equation being formals. And so what this is going to give us is two divided by four times V one, which will be V one times 10.5. And so because our final volume of our gasses is equal to V1 times .5 and we understand .5 is 50%. We can confirm that choice. A is the only correct answer choice to complete this example because our final volume of our gasses is going to decrease by 50%. So I hope that everything I explained was clear. If you have any questions, please leave them down below and I will see everyone in the next practice video.