Rhenium has two naturally occurring isotopes Re - 185 with a natural abundance of 37 40%, and Re - 187 with a natural abundance of 62 60% the sum of the masses of the two isotopes is 371.9087 amu Atomic mass of Re is 186 207 amu Find the masses of the individual isotopes. Express your answer using six significant figures.

individual isotopes

Re 185 = 139.094

Re 187 = 232.815

Explanation:Correcting the typo error for natural abundance as 37 40 as 37.40 and 62 60 as  62.60

Answer is found as follows

For Re 185 natural abundance  37.40%

  371.9087 x 37.40/100 = 139.0938538

six significant figures after rounding off = 139.094

For Re 187  natural abundance 62.60

371.9087 x 62.60/100 = 232.8148462

six significant figures after rounding off = 232.815

4

Explanation: