1. 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.

2. 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

3. 23.985 x.7899 = 18.95 24.986 x.1000 = 2.499 25.982 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

4. 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