A sample of rubidium contains two different isotopes. 72.15% of the sample

Chemistry

1 answer:

Leona [35]2 years ago

4 0

Answer:

Average atomic mass = 85.557 amu.

Explanation:

Given data:

Percent abundance of Rb-85 = 72.15%

Percent abundance of Rb-87 = 27.85%

Average atomic mass = ?

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100

Average atomic mass = (72.15×85)+(27.85×87) /100

Average atomic mass = 6132.75 + 2422.95 / 100

Average atomic mass = 8555.7 / 100

Average atomic mass = 85.557 amu.

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