Suppose that an element has two isotopes. The average atomic mass of the element is 45.737 u . One isotope has a mass of 40.149 u and an abundance of 37.46 % . Calculate the mass of the second isotope.

The answer to your question is 49.08 u

Explanation:

Data

Average atomic mass = 45.737 u

Isotope 1 = 40.149 u   abundance = 37.46%

Isotope 2 = ?

Process

1.- Calculate the abundance of isotope 2

abundance isotope 1 + abundance isotope 2 = 100%

                       37.46 + abundance isotope 2 = 100

                                    abundance isotope 2 = 100 - 37.46

                                     abundance isotope 2 = 62.54

2.- Calculate the mass of isotope 2

Average atomic mass = (abundance x mass isotope 1) + (abundance x

                                                                                            mass isotope 2)

45.737 = (0.3746 x 40.149) + (62.54 x mass isotope 2)

mass isotope 2 = [45.737 - (0.3746 x 40.149)]/ 62.54

mass isotope 2 = [45.737 - 15.0398]/ 62.54

mass isotope 2 = 30.6972/62.54

mass isotope 2 = 0.4908 x 100

mass isotope 2 = 49.08 u