Worksheet 3 September 17 Chapter 21. Chromium has the following isotopic mass and abundances (%)IsotopeAtomic mass (amu)Abundance (%)Cr-5049.94614.35Cr-5251.940583.79Cr-5352.94079.50Cr-5453.93892.36Calculate the atomic mass (average mass) of a sample of naturally occurring chromium.
2. There are two stable isotopes of the element gallium. Their masses are 68.92558 amu and 70.9247050 amu. If the average atomic mass of gallium is 69.7231 amu, what is the natural % abundance of the lighter isotope?
PLAN: You have two unknowns: % abundance of Ga-69 and the % abundance of Ga-71. must express both unknowns in terms of one variable, x; what relationship between the two % abundances can you use to do that?You 1