Exam Questions

Question 1

A sample of titanium contains 4 isotopes, 46Ti, 47Ti, 48Ti & 49Ti. This sample has a relative atomic mass of 47.8. The ratio of abundance of isotopes 46Ti, 47Ti & 49Ti is 2:2:1. Calc the % abundance of 46Ti in this sample

Answer 1

Ar = (Σ% abundance x mass isotope)/100
% 49Ti = x
% 46Ti = 2x
% 47Ti = 2x
% 48Ti = 100-5x
47.8 = [(46x2x) + (47x2x) + 48(100-5x) + 49x]/100
47.8 = (235x + 4800 - 240x)/100
5x = 20
x=4
%46Ti = 2x = 8%