00:01
All right, we want to find the mass of zinc in this penny.
00:03
And so we do a reaction and we evolve a gas that tells us essentially how much zinc we have.
00:09
And the gas is at 35 degrees c, has a volume of 925 millimeters, and that pressure of 775 milligrams, millimeters of hg.
00:22
And so we can use the ideal gas law, pv equals nrt, to help solve the moles of substance that is in this under these conditions here.
00:35
And so what's rearranged this is sulfur in.
00:38
Pv over rt is equal to the number of moles of gas we have.
00:43
Well, we know all these conditions.
00:48
The thing is none of the units match up because the r i'm going to use is 0 .0821 liters, atmospheres, moles, and calvins.
00:57
So what we'll want to do is convert all these so the units match these units of r.
01:04
So 35 degrees c plus 273 gives us 308 kelvin.
01:14
925 mil liters, divide by 1 ,000 millimeters per liter, gives a 0 .925 liters.
01:22
And 775 mhg, divide by 760 mmhg, divide by 760 mmmmm.
01:30
Hg per 1 atmosphere gives us 1 .019 atmospheres.
01:39
And let's round that up a bit, 102 atmosphere...