00:01
The average atomic mass for arridium is 192 .22 amus.
00:06
If arridium 191 has an atomic mass of 190 .961 amus, and the abundance is 37 .3 percent, and arridium 193 is the only other natural occurring isotope, what is the atomic mass for aridium 193? so the first thing we're going to need to do is figure out the percentage, and all we do, is we take 100 minus 37 .3, and that will give us the percentage of a radium 93.
00:37
So let's do that.
00:39
100 minus 37 .3.
00:41
That's going to equal 62 .7%.
00:44
Now let's convert these percents to decimals to 1 .73, and then 0 .627.
00:53
So our average atomic mass is 192 .22.
00:59
That has to equal the amount of arridium 191, so 190 .961, times its percentage, 0 .373, plus 0 .627%, or the decimal form of arridium 193.
01:19
So now we just have to solve for x.
01:22
So we'll take 0 .627x is equal to 192 .2.
01:31
Point 961 times 0 .373 or x is equal to 192 .22 minus 190 .961 times 0373 all over 0 .627.
01:54
So let's do this math and give us a little more room...