00:01
Okay, so here we have this question.
00:02
How many grams of sodium chloride should be used in compounding the following prescription? so we have all these elements, these ingredients in this equation.
00:11
Let's go back down here.
00:12
We have all these ingredients, and so what i've done is i've set up a table where this is ingredient one, here's ingredient two, ingredient three, and ingredient four, right? okay, so let's walk our way through the information that we're given here.
00:25
So first of all, the mass per mass percent that we're given is one, 1 % phenact, whatever that is, 1 % of that, half a percent of chlorobutinol, 0 .9 % of sodium chloride, and that leaves the rest is going to be water.
00:42
It's 97 .6%, right? because it all has to go up to 100%.
00:46
So then what we do is we say, all right, well, if that's the case, if that's the percent, what is the mass per 100 grams, right? so it's going to be the same thing, because that's the definition of mass percent.
00:56
That's mass of the ingredient per 100 grams of the total, right? and so the next thing we do is we say, if that's true, how many grams are we going to have in here? and we don't know the actual mass, we don't know for the first three, but we do know for the third one.
01:14
It's 60, right, because we're given 60 mils, and water has a density of one gram per mill, so it's 60 mils...