Chemistry
Beanium Lab
Name __________________
Period ________
Palatine, IL – Nuclear chemists, performing basic research on dirty silverware and
plates in local restaurants today, discovered what is believed to be element number
119. The researchers have named this element “Beanium,” derived from the small
vegetables that grow on climbing leguminous plants.
Further research of the new element will be conducted in the laboratories at Fremd
High School. Many chemistry students have generously volunteered their time to
help with the follow-up experiments involving the new element.
A reliable source was overheard saying the first experiments will determine how
many isotopes of the element exist. After finding how many isotopes comprise the
element, researchers will look for the atomic mass of each isotope. Finally, the
weighted average mass will be determined which will become the atomic mass of
the element “Beanium.”
Pre-Lab Questions
1. Which of the following would be considered a set of isotopes? (Mark all that
apply).
a. 146 C and 147 N
b. 105 B and 115 B
20
22
c. 10
Ne and 10
Ne
40
40
d. €20 Ca and 19 K
€
€
€
2. What is the basic atomic difference between isotopes of the same element?
€
€
€ 3. What
€ does the term “relative percent abundance” mean?
4. If there are 100 garbanzo beans, 27 pinto beans and 173 lentil beans in a bag,
what is the percent composition (by number) of each type of bean in the bag?
5. Suppose your chemistry grade was broken down so that 70% of it was based
on exams, 20% on labs and 10% on homework. If you average scores are 85
on exams, 75 on labs and 96 on homework, what would your weighted
chemistry average be?
Method:
+
+
Lab Percentage (Switched into decimal form) X Average Lab Score
Exam Percentage (Switched into decimal form) X Average Exam Score
Homework Percentage (Switched into decimal form) X Avg. HW Score
=
Weighted Chemistry Average
Procedure: Write down your bag # here for future reference: ___________!
Quick Tip –
Lentil =
Little Green
Ones
Pinto =
Brown Ones
Garbanzo =
Popcorn-ish
At your lab station is a bag containing a sample of the new element
“Beanium.” The differences between the isotopes of this element are very
distinct. Each different type of bean represents an isotope of the element.
Each individual bean represents an atom of “Beanium.” Please read the
following steps and prepare a data table before you enter the research facility!
1. Sort the Beanium atoms into groups, each group representing a different
isotope.
2. Record the total number of atoms per isotope. Be sure to also record the
total number of atoms in your bag.
3. Record the mass of each of the different isotopes. (Be sure to get the mass
of the whole pile – not the mass of an individual atom)!
Calculations/Graphing:
1. Determine the relative percent abundance (by number) of each isotope.
2. Determine the atomic mass per atom of each isotope. This gives the
average mass of a single atom of the isotope of interest.
3. Determine the weighted average atomic mass of “Beanium.”
4. Find another group that has the same “element” as you (either A, B or C).
Compare your lentil data with that group. Are the atomic masses of that
isotope the same? Are the percent abundances the same? Do the same for
the other isotopes (pinto, garbanzo).
5. Create a pie graph using Excel showing the relative percent abundances of
the isotopes for your group. Enter your data in a manner similar to the
table below, click on the chart wizard button and follow the “directions.”
Be sure to title your graph and show the percentages of each type of
isotope.
Type of Bean
# of Beans
Lentil
Pinto
Garbanzo
Questions for Discussion:
1. Briefly summarize how a weighted average atomic mass is calculated for
an element.
2. Should many different trials be performed to get a better value for the
average atomic mass of Beanium? Why?
3. Why were you instructed in procedure step #3 to get the mass of the
entire pile of each type of isotope instead of getting the mass of an
individual atom?
4. This activity provides a model by which average atomic mass can be
determined for “Beanium.” In what ways is this activity a good model
(how does it similar to the actual process of calculating weighted average
atomic masses on the periodic table)? In what ways does the model fail
when compared to calculating the average atomic mass for real elements?