00:01
In this problem, we're being asked to figure how many phosphorus atoms are present in one gram of three different compounds.
00:07
The first compound we are asked to work with is p406, which has a molar mass of 219 .88 grams per mole, which we figure out by taking the molar mass of four phosphorus plus six oxygen and adding that together.
00:28
And we know that one mole is 6 .022 times 10 to the 23rd.
00:33
So we know that we're given one gram of this compound of p406, and we know that one mole of this is 219 .88 grams, which then is going to allow our, grams p .04 to divide out.
01:05
Then we can multiply that by 6 .022 times 10 to the 23rd molecules per mole.
01:28
And then finally, this compound has four phosphorus per molecule.
01:37
So, we've gone from grams of the compound to phosphorus atoms.
01:52
And when we go through and do the multiplication and division and finish our dimensional analysis, we get that there are 1 .096 times 10 to the 22nd phosphorus atoms.
02:13
In one gram of p406.
02:18
Now for this one we're going to do the same thing, but with ca3, p .o42, which has a molar mass of 310 .18 grams per mole...