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:1. Take a cupful of beans from

the mixed pile. This is the random sample.

2. Separate the beans by type.3. Measure and record the

mass of each type of bean on the balance.

4. 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

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

Group Data

Class DataGroup Relative Mass of Beanium1 2

3

4

5

6

7

8

9

Average APercent Error

A - O% E = x 100

A

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)

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.

• Homework: In your Chemistry notebook– Practice Problems: 16-17 pg 118

: 18-19 pg 121

4.3 Assessment pg 121