00:01
For this question, we're given a molarity of an unknown aqueous solution, and then we're given the information for pure water at 20 degrees celsius.
00:15
Part a wants to know what is the vapor pressure of the solution.
00:22
So to find the vapor pressure of solution, we need vapor pressure of h2o times the mole fraction of our solute.
00:32
I'm sorry, that should be times the mole fraction of the solvent.
00:37
And then this is given that we have 1 .9m, which means we've got 1 .9 moles in 1 ,000 grams of h2o.
00:52
So to get the mole fraction of our solvent, we're going to do moles of solute divided by total moles, which is going to give us our 1 .9 over our 1 .9 divided by our 1 ,000 grams over our 18 grams, giving us 1 .9 over 56 .64, which is going to give us 0 .092, and this comes down to 0 .02.
01:23
I went ahead and put that up there.
01:26
Now we need to get the mole fraction of the solvent is 1 minus the mole fraction.
01:32
Of solute.
01:33
So we're going to do one minus our 0 .02 giving us 0 .98 for our solvent.
01:42
Now we're just going to do the 17 .5 tour that was given to us in the question and we're going to multiply this by our solvent which is our .98...