00:01
So this is really no different from our traditional osmotic pressure questions where we have the osmotic pressure equals i -crt, just a little bit of extra work after we're done, just dealing with some units and conversions.
00:14
So we're told that it's a non -electroids, so i is one, so ignore it.
00:19
Concentration is what we're looking for, r and t, or we have that.
00:23
So the osmotic pressure is 4 .89 atmospheres to equal to the concentration.
00:31
Which is what we're looking for are we're gonna have that's our gas constant so 0 .0821 liters atmosphere per mole kelvin this is the gas constant i'm most comfortable ones.
00:41
That's the one i use but whatever you do choose you have to make the units cancel out the temperature we have is 25 degrees celsius, but we need it in kelvin so add 273 we have 298 kelvin as our temperature quick note it's not degrees kelvin.
00:59
It's just kelvin a little bit confusing, but you know so it's frustrating to see people not know that and say degrees kelvin.
01:07
You just say kelvin.
01:09
So the kelvin cancels out.
01:13
Atmospheres cancel out.
01:15
Concentration, you'll see you'll have to be in moles per liter as we would want.
01:18
And we find that our concentration then is equal to 0 .190 moles for every single liter of the solution we have.
01:28
I wrote it like this instead of just as a molarity, because the next step we want to do is figure out how many moles we have...