What is the average atomic mass of gold if half of the gold found in nature has a mass of 197 amu and half has a mass of 198 amu?

1 Answer
Nov 28, 2015

Answer:

#"Average mass"=197.5a.m.u.#

Explanation:

The average atomic mass can be calculated by:

#"Average mass"=sum("isotope mass")xx("percent abundance")#

If half of gold is found in nature with a mass of #197a.m.u.# therefore its percent abundance is #50%# and the percent abundance of the isotope #""^198Au# is also #50%#.

#"Average mass"=(197xx(50%)/(100%))+(198xx(50%)/(100%))=197.5a.m.u.#