Problem: Pretend that a new element with an atomic weight of 342.38 amu was recently discovered. 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? A) 348.67 B) 343.29 C) 345.55 D) 342.38 E) 350.21

FREE Expert Solution

We’re being asked to calculate the mass of a heavier isotope of an element. We can use the following equation:


Atomic Mass = mass×f.a.isotope 1 + mass×f.a.isotope 2 


Where:

atomic mass = average atomic mass of the element 

f.a. = fractional abundance of the isotope


To get f.a., we simply need to divide the given percent abundance by 100.


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Problem Details

Pretend that a new element with an atomic weight of 342.38 amu was recently discovered. 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?

 A) 348.67 

B) 343.29 

C) 345.55 

D) 342.38 

E) 350.21

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Isotopes concept. You can view video lessons to learn Isotopes. Or if you need more Isotopes practice, you can also practice Isotopes practice problems.

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