# how to find abundance of 206, 207 and 208 Pb

by subopolois
Tags: abundance
 P: 69 how would i find the abundance of Pb 206, 207 and 208 if im given the isotopic data of 207Pb/206Pb and 208Pb/206Pb?
 Sci Advisor HW Helper PF Gold P: 3,725 Pending...
 Sci Advisor HW Helper PF Gold P: 3,725 OK... Assume that the expression 206Pb means the molar fraction of lead-206. The same is true for 207Pb and 208Pb. You know that the molar fractions sum to 1 as well as the molar ratios of 207Pb/206Pb and 208Pb/206Pb. You can also calculate 207Pb/208Pb. From here it is merely solving for the simultaneous equations.
P: 69

## how to find abundance of 206, 207 and 208 Pb

 Quote by chemisttree OK... Assume that the expression 206Pb means the molar fraction of lead-206. The same is true for 207Pb and 208Pb. You know that the molar fractions sum to 1 as well as the molar ratios of 207Pb/206Pb and 208Pb/206Pb. You can also calculate 207Pb/208Pb. From here it is merely solving for the simultaneous equations.
ok, i think i get it. heres my scenerio,
the Pb content is 468ppm
207Pb/206Pb= 0.2515
208Pb/206Pb= 0.0581
i could just use abgebra to find each right?
206=x
207=0.2515x
208=0.0581x
i just solve for x and put it back into the previous equation?