Calculate the work done in joules by a chemical reaction if the volume increases from 3.2 L to 3.4 L against a constant external pressure of 3.6 atm. What is the sign of the energy change?

Video transcript

hi everyone. This problem reads, determined the sign and amount of work performed by a chemical reaction in which the volume reduced from 4.5 liters to 3. liters at constant 2.3 atmospheres. Okay so the question that we want to answer here is the sign and amount of work done and for work, the units that we're going to want is jules okay or kill a jewels. And so we need an equation that is going to relate work with volume and pressure. Okay. And that equation is work is equal to negative pressure. Times change and volume. So let's write out what was given in the problem. So the pressure given is 2.3 atmospheres and the volume given. So are we're going to take our final volume which is 3.4 liters. So our final volume minus our initial volume is 4. liters. So our change and volume Equals negative 1.1 leaders. So let's go ahead and plug these values in. So we have work is equal to negative pressure, so that's going to be negative. 2.3 atmospheres times change in volume which is negative 1.1 L. So when we do this calculation we get work is equal to 2.53 atmospheres. Times leaders. Okay, but we want the unit of work and jewels. Okay, so we're going to go from atmospheres Times Leaders to jules and the conversion that we're going to use for this is one atmosphere. Times leaders is equal 101.3-5 jewels. Okay, so let's go ahead and do that conversion here. So we have one atmosphere times leader is equal 101.3- jewels. All right, so looking at our units we see that atmospheres time leaders cancel and we're left with a unit of jewels which is what we want. So the calculation we're going to do is 2.53 times 101.325. And when we do this calculation we're going to get work is equal to 256 jewels. So let's recall that work can be in either jewels or kill a jules. Let's go ahead and convert this To a decimal. OK, so we're going to get we'll leave it in jewels but we'll convert this to a decimal and this is going to equal 2.6 times 10 to the two jewels. And this will be our final answer. So the sign is going to be positive. So let's go ahead and write the sign. So we have positive. That's the sign and the amount is 2.6 times 10 to the second jewels. That is it for this problem. This is the final answer. I hope this was helpful