Calculate the molar mass of the noble gas
krypton in a natural sample, which is 0.8%
78Kr (molar mass 77.92 g/mol), 1.95% 80 Kr
(molar mass 79.91 g/mol), 10.68% 82²Kr (mo-
lar mass 81.91 g/mol), 11.95% 8³Kr (molar
mass 82.92 g/mol), 57% 84Kr (molar mass
83.91 g/mol), and 17.62% 86Kr (molar mass
85.91 g/mol).
Answer in units of g/mol. Your answer
must be within _+ 0.001%