1. Education
Send to a Friend via Email
You can opt-out at any time. Please refer to our privacy policy for contact information.

Discuss in my forum

Atomic Mass and Atomic Abundance Example Chemistry Problem

Worked Chemistry Problems

By

Atomic Abundance Example Chemistry Problem:

The element boron consists of two isotopes, 105B and 115B. Their masses, based on the carbon scale, are 10.01 and 11.01, respectively. The abundance of 105B is 20.0%.
What is the atomic abundance of and the abundance of 115B?

Solution

The percentages of multiple isotopes must add up to 100%.
Since boron only has two isotopes, the abundance of one must be 100.0 - the abundance of the other.

abundance of 115B = 100.0 - abundance of 105B

abundance of 115B = 100.0 - 20.0
abundance of 115B = 80.0

Answer

The atomic abundance of 115B is 80%

How To Calculate Atomic Mass

©2014 About.com. All rights reserved.