Mass of Pennium: Average Atomic Mass of Isotopes

Old and new pennies

Triple beam balance

1. Count and record the number of each kind of penny: old and new. 
   
   (isotope A) # of old pennies = _____
   
   (isotope B) # of new pennies = _____

2. Calculate the percentage of occurrence of each isotope.

3. Find the mass of one old penny and the mass of one new penny.
   
   Mass of isotope A = _____ g
   
   Mass of isotope B = _____ g  

4. Calculate the average atomic mass of pennium.

 

This will be the experimental value for the mass of pennium.

5. Now, calculate the average atomic mass by massing ALL the pennies and dividing by the total # of pennies.

This will be the theoretical value for the mass of pennium.

 

6. Calculate the % error.