Time management is very much important in IIT JAM. The eduncle test series for IIT JAM Mathematical Statistics helped me a lot in this portion. I am very thankful to the test series I bought from eduncle.
Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Neelam Kumari posted an Question
June 02, 2021 • 19:54 pm
![]()
30 points
30 points
- UGC NET
- Commerce
Naturally occurring rubidium consists of just two isotopes. one of the isotopes consists of atoms having a mass of 84.912 amu; the other of 86.901 amu. what is
Naturally occurring rubidium consists of just two isotopes. One of the isotopes consists of atoms having a mass of 84.912 amu; the other of 86.901 amu. What is the percent natural abundance of the heavier isotope?
1 Answer(s)
Answer Now
- 0 Likes
- 2 Comments
- 0 Shares
Do You Want Better RANK in Your Exam?
Start Your Preparations with Eduncle’s FREE Study Material
- Updated Syllabus, Paper Pattern & Full Exam Details
- Sample Theory of Most Important Topic
- Model Test Paper with Detailed Solutions
- Last 5 Years Question Papers & Answers
Sign Up to Download FREE Study Material Worth Rs. 500/-
Rucha rajesh shingvekar![best-answer]()
The average atomic mass of Rb is 85.47 amu. This is the weighted average of the masses of the two naturally occurring isotopes. A weighted average is calculated by multiplying the percent abundance of the 84.912 amu isotope by its mass and adding this value to the product of the percent abundance of the 86.901 amu isotope and its mass. The Periodic Table confirms an average atomic mass for Rb=85.47 amu. Let x equal the percent abundance of the 86.901 amu isotope, and let (1−x) equal the percent abundance of the 84.912 amu isotope. 85.47=x(86.901)+(1−x)(84.912) 85.47=86.901x+84.912−84.912x 1.989x=0.558 x≈0.28or 28% Ans is 28%