00:01
All right, so we have a cylinder with a movable piston in it, and we have one mole of an ideal gas inside of this, and it's initially at a temperature of 8 degrees celsius, which is 281 kelvin, and we're told that the piston, the gas is heated up at constant pressure, sorry, i keep screwing the strong up, the gas is heated up at constant pressure until the final volume of this gas is 8 times the initial.
00:30
Volume.
00:32
And the initial pressure, by the way, is one atmosphere.
00:34
So p, i will just say, it's 101 .35 ,000 pascal.
00:41
That's atmospheric pressure.
00:43
And we want to know what's the final temperature of the gas and what's the work done on the gas.
00:48
Well, if this is done at constant pressure, we can look at our ideal gas law.
00:51
It says pv equals nrt.
00:54
If p is constant, what that means is t over v is constant for a constant pressure process, and we're not adding or subtracting any gas either, so we don't need to worry about that.
01:05
So then what that means is that the initial temperature over the initial volume is equal to the final temperature over the final volume.
01:14
And so we can solve for the final temperature by just multiplying by the final volume of both sides.
01:19
So we have the final volume over the initial volume times the initial temperature.
01:23
And these temperatures have to be in kelvin for this to work...