00:01
To determine the moles present in a liter of the solution, we start with 1 .00 liters, and we convert those liters into grams by multiplying by a thousand, well, liters into milliliters by multiplying by a thousand, and then into grams by multiplying by density.
00:23
There are 1 .2089 grams for every 1 milliliter.
00:33
Once we have grams, we can convert it into kilograms and 1 liter, 1000 grams for 1 kilogram, and 1 liter would be 1 .2089 grams of the solution.
00:57
But we need to figure out the moles of just the solute.
01:13
So molality 5 .257 is the moles of the solute that we need to figure out per kilogram of just the solvent.
01:28
The kilogram of just the solvent is going to be, we go back to this, this was supposed to be kilograms, is going to be the kilograms of the solution, 1 .2089, minus the kilograms of phosphoric acid, which will be the moles of phosphoric acid, we don't know that yet, converted into grams using its molar mass the molar mass of phosphoric acid will be the mass of one mole of phosphorus, three moles of hydrogen, and four moles of oxygen, which is 97 .994 grams for every one mole.
02:32
And then then we convert those grams into kilograms.
02:35
1 ,000 grams is 1 kilogram.
02:38
This is the kilograms of the solution.
02:41
We subtract off the kilograms of the solute, knowing it's moles...