# isotopes-of-pennynium by ashrafp

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```									             Average Atomic Mass of “Pennynium”
A Study of Isotopes
Introduction

In the production of pennies through the years, there have been a number of factors that have
determined the materials used to make them. The largest factor, however, is cost. If the value of
the material which makes up something is worth more than that item, than it doesn’t make sense
to create the item with that particular material.

As everyone knows, pennies are made of copper. What is less known is that zinc is also used to
create pennies. The zinc and copper are melted down and mixed together to create what is
known as an alloy. Over the years the proportions of zinc and copper have changed because the
value of copper has increased. One can easily determine which pennies have a high percentage
of copper because they have a larger mass than those that have a higher percentage of zinc.

In this lab, we are going to treat pennies as the element “pennynium.” Pennynium has two
different isotopes (atoms of the same element which have different masses.) It is your job to
determine the mass of the two different isotopes and also determine what year the new isotope
was created. After doing this, you will determine the average atomic mass of pennynium.

Objectives

1. Determine the individual masses of the two isotopes of pennynium.

2. Identify the year that the new isotope was created and the old isotope disappeared.

3. Determine which isotope contains a higher percentage of copper and which contains a higher
percentage of zinc.

4. Calculate the average atomic mass of pennynium.

Materials

20 atoms of pennynium, mixture of isotopes
electronic balance

Procedure

1. Find the mass of each atom of pennynium and record the year and mass on your data table 1.

2. Rewrite you data in increasing year order on data table 2.
Data

Data Table 1                                               Data Table 2
Year              Mass (g)                                 Year             Mass (g)

Data Analysis (You MUST show all of your work for credit!)

1. On data table 2, draw a line (in a different color) between the two distinct isotopes. This is
found by determining where the mass of the pennynium seems to have a sudden change.

2. Find the average mass of your first isotope of pennynium. Also find the average mass of your
second isotope of pennynium. These values represent the mass of one atom of pennynium.
Record these values below.

mass of isotope 1 = __________                         mass of isotope 2 = ___________

3. What percentage of your coins are isotope number 1? What percentage of your coins are
isotope number 2?
(Remember: % = (part/whole) x 100)

% isotope 1 = _________                                            % isotope 2 = __________
4. Calculate the average atomic mass of pennynium.

(% isotope 1)(mass of isotope 1) + (% isotope 2)(mass of isotope 2) = average atomic mass

Average atomic mass of pennynium = _________

Questions
1. Define isotope:
__________________________________________________________________

__________________________________________________________________

2. What subatomic particle is responsible for determining isotopes? _______________

3. Which subatomic particle has the same mass as the subatomic particle in question number 2?

__________________

4. Using the information in the introduction, determine which isotope of pennynium is made with

a larger amount of copper? _______________________

5. What explanation can you give for the creation of the new isotope of pennynium by our

government? ____________________________________________________________

_____________________________________________________________________________

_________

6. Are both isotopes of pennynium accepted at your local store? ________

Of course they’re both accepted! They’re both pennies. In the same way, different isotopes of
the same element still have the same chemical and physical properties of that element. The
different isotopes just have different atomic masses. Carbon with an atomic mass of 12 and
carbon with an atomic mass of 13 are both still carbon. They just have different numbers of
neutrons, but each still has 6 protons!

7. Sulfur has 4 isotopes: sulfur-32 is 95.0%, sulfur-33 is 0.76%, sulfur-34 is 3.22%, and sulfur-36 is
0.89% abundant. Calculate its average atomic mass.

8. The calcium atom has 6 naturally occurring isotopes. Their percentages are: 40Ca is 96.947%, 42Ca is
0.346%, 43Ca is 1.083%, 44Ca is 1.083%, 46Ca is 0.366% and 48Ca is 0.090%. Calculate its average
atomic mass.

9. Iron has 4 isotopes and their percentages are: iron-54 is 5.82%, iron-56 is 91.66%, iron-57 is 2.19%, and
iron-58 is 0.206% abundant. Calculate its average atomic mass.
Average Atomic Mass of “Pennynium”
A Study of Isotopes
Make-Up Data

Data Table 1                                               Data Table 2
Year              Mass (g)                                 Year             Mass (g)
1988               2.54
1997               2.53
1994               2.49
1964               3.15
2004               2.52
1996               2.52
1999               2.51
1995               2.50
1996               2.50
2005               2.52
1993               2.49
1997               2.52
1994               2.53
2001               2.51
1978               3.14
1961               3.13
1973               3.12
1981               3.11
1997               2.53
1977               3.14

Data Analysis (You MUST show all of your work for credit!)

1. On data table 2, draw a line (in a different color) between the two distinct isotopes. This is
found by determining where the mass of the pennynium seems to have a sudden change.

2. Find the average mass of your first isotope of pennynium. Also find the average mass of your
second isotope of pennynium. These values represent the mass of one atom of pennynium.
Record these values below.

mass of isotope 1 = __________                         mass of isotope 2 = ___________

3. What percentage of your coins are isotope number 1? What percentage of your coins are
isotope number 2?
(Remember: % = (part/whole) x 100)

% isotope 1 = _________                                            % isotope 2 = __________

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