The Incredibly Fun & Tasty Atomic Mass of Candinium Lab

(LAB GUIDELINES: 1,2,3,6,7,9,10,11,12)

Purpose:

To develop a strategy for determining the atomic mass of a fictional element called candinium, which has 3 isotopes: ______, ______, and ______.

Procedure:

You must write a bulleted step by step procedure keeping the following in mind:

Analyze your individual sample of candinium in order to complete the following data table. Remember: do not eat up your sample until you are sure that you have filled in the table correctly! (Also, you are not allowed to consider the mass of the entire sample in solving this problem, as the sample tends to rapidly oxidize, lose electrons, and explode when all isotopes are placed on a balance together.)

Data:

Total # of candinium atoms in sample______

Isotope / # of atoms of this isotope present / total mass of all the atoms of this isotope / Avg. mass of this isotope
(show calc.) / % abundance of this isotope
(show calc.)

Also, enter your data from the final two columns of your data table into the Google Sheets Spreadsheet using a lab computer.

Print the class data from Google Sheets to include in your lab report. Don’t forget to include a data table like the one above as well, for your group’s individual data.

Calculations:

Now, using only the last two columns of your data table, calculate the average atomic mass of candinium for your specific sample. Show your work.

Also, using the average class data for the last two columns, calculate the average atomic mass of candinium for the class data.

Questions:

1) Complete the following problems from your book: Chapter 3 – page 128, #’s 37, 39, 41, 43.

2) Explain the concept of a weighted average, and how it applies to the determination of the average atomic mass of the elements on the Periodic Table. Consult 3.1 and 3.2 of your book for assistance if necessary.

3) Include a labeled schematic diagram (from the Internet) of a mass spectrometer and explain in detail how it operates.

Error Analysis:

Calculate your percent error, using the class average as the accepted value.

Comment on why all groups do not get the same value for the average atomic mass of candinium.

So why does a mass spectrometer always calculate the same value for the average atomic mass for any given element?

Conclusion:

Write a conclusion in which you: restate the purpose, summarize your procedure and data recorded, explain the math, and finally give your results. Also, in your conclusion, explain the concept of a weighted average, and how it applies to the determination of the average atomic mass of the elements on the Periodic Table.

Remember, here is a great guide for writing your conclusion:

1) Restate the purpose

2) Summarize the procedure and data collection

3) Discuss any important principles / equations used

4) Explain the graphs and/or math

5) Report your results

Also, please include any other interesting information you would like to add.