 So this one says as a system increases in volume it absorbs 52.5 joules of energy in the form of heat from the surroundings The piston it's working against is at a pressure of 5.5 atm The final volume of the system is 58.0 liters What was the initial volume of the system if the internal energy of the system decreased by 103.4 joules So this is one like once that we had done at the beginning of the chapter and It's incorporating both heat and internal energy So you got to remember the equation for internal energy Delta E equals q plus delta E and in the case of These chemical equations. It's going to be WPB And if you want to recall WPB equals the negative P of the atmosphere So let's go ahead and write down the things that it gives us here So the reason I wanted to do this is because we want to think about what it's saying and what sign Our energies are going okay, so when it says it absorbs 52.5 joules of energy in the form of heat it means it's gaining it, right? So that means plus 52.5 joules Okay, so remember heat is q so in this case q It's going to be what did I say? 52.5 joules or if you want to plus 52.5 joules It says the piston is working against an external pressure of 0.550 ATM So that one's pretty straightforward. It gives us the final volume of the system So VF is 58.0 liters It says that we're looking for VI so we're going to have to find delta V first, right? And it also says the system increases in volume So we should expect VI to be smaller than VF and then it also says what's the initial volume of the system? Right what we're looking for if the internal energy of the system decreased by a hundred and three point four joules, so that means delta E So it decreased right so it's negative 103.4 Is everybody okay with those directions of those signs? So that's the thing you want to remember The probably the hardest thing about these types of problems Okay, so let's just go ahead and I guess the first thing we probably want to do is solve for work So work PV It's got an equal Delta E and then we're going to take this over to the other side. So minus q So we could just go ahead and solve for it now 103.4 Minus we know that that's negative P atm delta V Delta V. So we've got this is going to be delta V is going to be 155.9 joules divided by P atm So joules per atm. That's a weird volume unit, right? Okay, so So we're going to have the multiplier So in this case we get two eight three Point four five and we'll just keep it all the way out for right now joules per one atm Okay, so hopefully That hopefully you guys can see that there's going to be a conversion involved here, right? So because joules atm this is actually a volume unit. It's leaders, but To make it look like leaders. We've got to convert it 101.3 joules is one leader atm You guys remember that so this will be given to you this conversion factor, but you've got to know when to use it So we're going to cancel there cancel there cancel there cancel there cancel there And then we get units that make sense to Have for change of volume. So divided by 101.3 two point 80 we'll just do two three six six now It'll be here. This is the change in volume. So the initial volume is going to be Yeah, bf minus Delta b right because of course Delta b equals bf minus Okay, so bf they give to us. Hopefully if I remember 58.0 The long problem minus 282.80 leaders so To one decimal place after everybody okay with that being the initial volume Do you guys get that on your own? How about are there any questions on this one? There's a lot of uh steps. You know all the steps. So remember just plug in equations here and there. No questions Okay, good job