Question

If element L has 2 isotopes, one with a mass of 67 amu and a relative abundance of 55%, what is the average atomic mass if the other isotope has a mass of 72amu?

Answer 1

Answer: 69.25 AMU

Step-by-step explanation:

1. find missing %

knowing the first % abundance is 55 you are left with 45%

2. set up an equation

(55% * 67) + (45% * 72) = x

3. solve

(55% * 67) + (45% * 72) =x | break down to solve each part

55% * 67 =36.85 | can be done many ways ex: (55 * 67)/100 or .55 * 67

45% * 72= 32.4| can be done as previously expressed

36.85+32.4=69.25 AMU