00:01
Okay, so we know that borne has two naturally occurring isotopes, which is b -10, and it has a mass of 10 .03amu, and b -11, and it has a mass of 11 .009.
00:15
I want to calculate the percent abundance for each isotope if the average atomic mass is 10 .81.
00:21
So when we calculate average atomic mass, we know that it's going to be equal to some percent times one of the isotopes.
00:34
Plus some percent times the other isotope.
00:39
And these two percentages must add up to 100%.
00:43
And so when x and y are the two percentages, those are going to be in decimal form, which means x plus y is going to be equal to 1.
00:52
100 % here.
00:54
So if we wanted to solve for the percent abundance for one of these, we could actually say x is equal to 1 minus y...