calculate the average atomic mass of element x in which the first isotope found in 28.5% abundance weighs 200.0 amu and the other isotope weighs 220.0 amu.
avgmass*100=28.5*200.0 + (100-28.5*220)
To calculate the average atomic mass of element X, you need to take into account the abundance (in percentage) of each isotope and its respective atomic mass.
Step 1: Convert the abundance of the first isotope to a decimal fraction. In this case, the first isotope has an abundance of 28.5%, so we divide it by 100:
28.5 / 100 = 0.285
Step 2: Calculate the contribution of the first isotope to the average atomic mass by multiplying its abundance by its atomic mass:
0.285 * 200.0 = 57.0 amu
Step 3: Calculate the contribution of the second isotope by subtracting the abundance of the first isotope from 1 (since the abundances of all isotopes add up to 100%), and then multiplying by the atomic mass of the second isotope:
(1 - 0.285) * 220.0 = 157.15 amu
Step 4: Finally, add together the contributions from each isotope to get the average atomic mass:
57.0 + 157.15 = 214.15 amu
Therefore, the average atomic mass of element X is approximately 214.15 amu.