1. Average Atomic Mass of Beanium
In this lab you will investigate the mass of three different types of the same atom of the element “Beanium” by taking a sample of this element and taking a weighted average of its three different types. Read the directions before beginning the laboratory activity. Modify the directions before proceeding if you see fit to do so.
SUGGESTED PROCEDURE:
Take a cupful of beans from the mixed pile. This is the random sample.
Separate the beans by type.
Measure and record the mass of each type of bean on the balance.
Count and record the number of each type of bean.
5. Record data and calculations in the data chart (see data chart below for details)
average mass of each isotope
percent abundance of each isotope
relative abundance of each isotope
relative mass of each isotope
average mass of all isotopes
Class average for relative mass
Percent error

2. Group Data Isotope Pinto Beans Kidney Beans Sunflower Seeds Totals
# (count)
Mass (g)
Average Mass (g)
Relative Abundance
# of individual beanium
Total # beanium
Percent Abundance
(Relative Abundance x 100)
Relative Mass
(Relative Abundance x Average Mass)
 O

3. Class Data A Group Relative Mass of Beanium 1 2 3 4 5 6 7 8 9 Average
Percent Error

4. Analysis Summarize what you did. Define the term isotope.
Compare the total values for rows 3 and 6 in the data table. How does the average mass differ from the relative mass?
Compare your value for relative mass to that of the class.
Comment on your percent error, sources of error in the activity, and provide suggestions for improvement.
Comment on how the activity is a model for calculating atomic mass of real elements.
Conclusion: The relative mass of Beanium is ____________ ± __________ % (this is the % error)

5. Conclusion
Describe how you could check your work to see if your calculated % mass of each of the element types was correct.
Design an experiment that you could use to check to see if the average mass of “beanium” you calculated was correct.
Read through your book, section 4.3 and determine which particle makes them different from each other.

6. Homework: In your Chemistry notebook
Practice Problems: pg 118
: pg 121
4.3 Assessment pg 121