Home
Class 9
CHEMISTRY
The average atomic mass of boron is 10.8...

The average atomic mass of boron is 10.8 u. If the isotopic mass of B-10 is 10.013 and that of B-11 is 11.009, then the relative abundance of these isotopes is respectively

A

80.1% and 19.9%

B

11% and 89%

C

20.98% and 79.02%

D

10.001% and 89.9%

Text Solution

Verified by Experts

The correct Answer is:
C
`10.8 = (10.013x + (100-x)11.009)/(100)`
`implies 1080 = 10.013x + 1100.9 - 11.009x`
`implies x = 20.98%`
`:.` Abundance of B-10 = 20.98%
Abundance of B-11 = 100-20.98 = 79.02 %
Promotional Banner

Topper's Solved these Questions

  • STRUCTURE OF ATOM

    SCIENCE OLYMPIAD FOUNDATION |Exercise ACHIEVERS SECTION (HOTS)|5 Videos

  • NSO QUESTION PAPER 2020 SET 1

    SCIENCE OLYMPIAD FOUNDATION |Exercise ACHIEVERS SECTION|1 Videos

Similar Questions

Explore conceptually related problems

B-10 isotopes

Boron has two isotopes, B-10 and B-11. The average atomic mass of boron is found to be 10.80u. Calculate the percentage of abundance of these isotopes.

An element is found in nature in two isotopic forms with mass numbers (A-1) and (A+3). If the average atomic mass of the element is found to be A, then the relative abundance of the heavier isotope in the nature will be :

In each of the following two questions two statements are given one labelled as the Assertion(A) or Statement I and the other labelled as the reason (R) or statement II. Examine these statements carefully and mark the correct choice as per following instructions Assertion (A) - Relative atomic mass of boron is 10.8 Reason (R) - Boron has two isotopes B-10 and B-11 with percentage abundance of 19.6% and 80.4% respectively.

Assertion : Relative atomic mass of boron is 10.8 Reason : Boron has two isotopes B-10 and B-11 with percentage abundance of 19.6 % and 80.4 % respectively.

Calculation of average atomic mass: The atomic attoms fo the two stbale isopes of boron, ._(5)^(10)B (19.78%) and ._(11)^(5)B (80.22%) , are 10.0129 u and 11.0093 u , respectively, Calculate the average atomic mass of boron. Strategy : The atomic mass of an element existing in nature as istopes is the weighted average of the istope masses, Thus, multiply the fracton of each isotope by its mass and add these numbers to obtain the mass of born.

The element bron occurs in nature as two isotopes havein atomic masses 10 u and 11 u . What are the percentage abundances of these isotopes in a sample of boron having average atomic mass of 10.8 u?

The natural boron is composed of two isotopes ._5beta^10 and ._5beta^11 having masses 10.003 u and 11.009 u resp. Find the relative abudance of each isotope in the natural boron if atomic mass of natural boron is 10.81u.