00:01
Alright, so we have 30 .4 grams of hydrochloric acid hcl, 11 .6 grams of water, and a total solution volume of 128 milliliters.
00:23
We want to know first what is the weight percent of hcl, or the percent by mass.
00:29
So that's going to be the mass of hcl, which is 30 .4 grams, over the total mass, so 30 .4 plus the 111 .6 grams of water, and we multiply that by 100 % to turn the decimal into a percentage.
00:56
This comes out to 21 .4 % to three significant figures.
01:03
Years.
01:05
All right, now we want to know the molality, lowercase m.
01:13
So that's going to be moles of hcl over kilograms of solvent, which is, so for the top, we'll take 30 .4 grams of hcl and divide by the molar mass, which is 36 .46 grams per mole.
01:39
And then on the bottom, we have 111 .6 grams of water.
01:45
It's 0 .1116 kilograms.
01:49
I just divided it by a thousand to convert.
01:55
This comes out to 7 .48, and the unit is molal, lowercase m.
02:06
All right, then we want the mole fraction, which is represented by the greek letter chi.
02:12
So that's going to be moles of hcl over total moles...