Class Set: Please do not write on this sheet
Unit 3: Atoms
Beanium Laboratory
Purpose To analyze the isotopes of Beanium and calculate its atomic mass.
Materials Sample of Beanium
 Balance
 Pencil
 Paper
Procedure1. Make a table similar to Figure A to record your data, and record your calculated
values
2. Obtain a sample of Beanium.
3. Separate the three isotopes (black, white, red) and measure the mass of each
isotope.
4. Count the numbers of black, white and red beans
5. Repeat steps 2-4 one more time.
Black
White
Red
Totals
Total Mass (Grams)
Number
Average Mass (Grams)
Percent Abundance
Relative Abundance
Relative Mass
Figure A
Calculations(All Calculations must be shown to receive full credit for the laboratory)
1. Calculate the average mass of each isotope by dividing its total mass by the
number of particles in the isotope.
2. Calculate the percent abundance of each isotope by dividing its number of
particles by the total number of particles and multiplying by 100.
3. Calculate the relative abundance of each isotope by dividing the percent
abundance from step two by 100
4. Calculate the relative mass of each isotope by multiplying its relative abundance
from step three by its average mass.
5. Calculate the average mass of all Beanium particles by adding the relative
masses. The average mass is the atomic mass of Beanium.
Class Set: Please do not write on this sheet
Analysis1. Explain the difference between percent abundance and relative abundance.
What is the result when you total the individual percent abundances? The
individual relative abundances?
2. The percent abundance of each kind of bean tells you how many of each kind of
bean there are in every 100 particles. What does relative abundance tell you?
3. Compare the total values for row three and row six in the table. Why can’t the
atomic mass of row six be calculated the way the total for row three is
calculated?
4. Explain any differences between the atomic mass of your Beanium sample and
that of your neighbor. Explain why differences would be smaller if larger
samples were used.