A new compound was recently discovered and found to have an atomic weight of 342.38 amu. This element has two isotopes, the lighter of which has a mass of 340.91 amu and an abundance of 68.322%. What is the mass of the heavier isotope?

The mass of heavier isotope is 345.6 amu.

Explanation:

Given dа ta:

atomic wight of compound = 342.38 amu

lighter isotope mass = 340.91 amu

abundance of lighter isotope = 68.322%

mass of heavier isotope = ?

Solution:

average atomic mass = (% age abundance of lighter isotope * its atomic mass) + (% age abundance of heavier isotope * its atomic mass) / 100

percentage of heavier isotope = 100 - 68.322 = 31.678

Now we will put the values in formula.

342.38 = (68.322 * 340.91) + (31.678 * X) / 100

342.38 = 23291.65302 + (31.678 * X) / 100

342.38 * 100 = 23291.65302 + (31.678 * X)

34238 - 23291.65302 = (31.678 * X)

10946.35 / 31.678 = X

345.6 = X

The mass of heavier isotope is 345.6 amu.