Average Mass Activity  

Find the average mass of all the spheres in the tray.  You may:

-Make no more than 3 mass measurements.-Mass only 1 sphere at a time

 Record all measurements and show your work.  Explain what you did and all assumptions.

63.5 amu

23. Calculate Copper has two isotopes: Cu-63 (abundance=69.2%, mass=62.930 amu) and Cu-65 (abundance= 30.8%, mass=64.928 amu) Calculate the atomic mass of copper..692 x 62.930 =

43.5 .308 x 64.928 = 20.0

23.985 x .7899 = 18.95 24.986 x .1000 = 2.49925.982 x .1101 = 2.861 24.31 amu

24. Three magnesium isotopes have atomic masses and relative abundances of 23.985 amu (78.99%), 24.986 amu (10.00%), and 25.982 (11.01%). Calculate the atomic mass of magnesium

Practice Problem  Silver is found in two isotopes with atomic masses 106.9041 amu and 108.9047 amu, respectively. The first isotope represents 51.82% and the second 48.18%. Determine the average atomic mass of silver.106.9041(0.5182) + 108.9047(0.4818) = 107.87 amu

55.40 + 52.47