Throughout this lab you are going to pretend that you have an element called "Pennium". You'll be given a bag of Pennium atoms. Through comparing the masses of the "penny atoms" you will see how many different Pennium isotopes are in the bag. You will then determine the average atomic mass of Pennium isotopes using the following equation: (average mass of isotope 1)(percent abundance of isotope1)+(average mass of isotope 2)(percent abundance of isotope 2). Now, you will choose another element (Fivecentium) to be accepted as the mass standard to which mass of Pennium, Dimeium, Quarterium, and Halfdollarium. All relative masses will be expressed in CMU (Coin Mass Units)
Objective: You will investigate the concept of atomic mass and how it was derived. You will develop your own unit of measure, the CMU, and use it to measure the relative masses of other coins. At the conclusion of this lab you will be able to explain how scientists developed the system for AMU's (atomic mass units) and how it is applied to determine the relative masses of other atoms of other elements.
Procedures- Part 1:
1- Obtain a packet of pennies.
2- Sort the pennies into two groups: pre-1982 and post-1982.
3- Measure the mass (in grass) of each stack of pennies. Record the mass (in grams) of each stack of pennies in a data table. Count the number of pennies in each stack.
4- Measure the mass in grams of a half dollar, quarter, nickel, and dime. Record these values in a data table.
5- Answer the questions below and then continue on with part 2.
Results: Pre-1982 Pennies Post-1982 Pennies
Mass: 42.4g 27.5g
Number of pennies: 14 11
Average mass: 3.03g 2.5g
Results Cont.: Nickel Dime Quarter
Mass: 5g 2.2g 5.1g
Mass in terms of nickel: 1N .44N 1.02N
Questions- Part 1:
1- Does each penny have the same mass?
*No each penny does not have to same mass.
2- Can you identify two "penny isotopes" based on the masses of the pennies? Explain?
*Yes!!! Pre-1982 is one isotope while post-1982 is another isotope.
3- What does your data tell you about the relationship between mass of a penny and date of a penny. Make a generalization.
*Pre-1982 pennies weigh more than the post-1982 pennies.
Procedures- Part 2:
1- Determine the average mass of pre-1982 pennies. (Record average).
*3.03g
2- Determine the average mass of post-1982 pennies. (Record average).
*2.5g
3- Determine the percentage of your pennies that is pre-1982 and the percentage that is post-1982. These percents should add up to 100%. What you have calculated is the percent abundance of each group of pennies (penny isotope).
*post- 44% pre- 56%
4- Let's choose one of your coins to make a CMU (coin mass unit). Let's say that the mass of a nickel (Fivecentium) is one CMU. Use the mass of a nickel to calculate the mass of a half dollar (Halfdollium), quarter (Quarterium), dime (Dimeium), pre-1982 pennies (Pre-82 Pennium), post-1982 (Post-82 Pennium). Again, show all calculations, and record all data in a data table.
5- Determine the average mass of a Pennium in CMU's using the percent abundance (from #3) of each pennium isotope (pre-82 and posst-82) and the mass of each pennium isotpope in CMU's (from #4).
*(3.03x.56)+(2.5x.44)=2.8
Questions AND Conclusions:
1- Make a statement about the average penny mass of pre-1982, post-1982, and pennies in te packet.
*New pennies, or post-1982 pennies, have more mass or are more massive than the pre-1982 pennies.
2- Explain how you derives the unit CMU.
*We used the formula given to us in the introduction. (3.03x.56)+(2.5x.44)=2.8
3- Using the idea you explained in #2 above, how did scientists obtain the Atomic Mass Unit (AMU) to measure the mass of atoms of different elements?
*They used atomic mass average base to help find all of the elements' atomic masses.
4- What is your weight in CMU's? (Remember 1lb=2.205Kg),
*.00635lb
5- Write a statement that compares what you did in this lab to what scientists have done to find the average atomic masses of the elements.
*Scientist have used the same method with Hydrogen as the smallest form of measurement to help find the atomic masses of the rest of the elements.
Procedures- Part 2:
1- Determine the average mass of pre-1982 pennies. (Record average).
*3.03g
2- Determine the average mass of post-1982 pennies. (Record average).
*2.5g
3- Determine the percentage of your pennies that is pre-1982 and the percentage that is post-1982. These percents should add up to 100%. What you have calculated is the percent abundance of each group of pennies (penny isotope).
*post- 44% pre- 56%
4- Let's choose one of your coins to make a CMU (coin mass unit). Let's say that the mass of a nickel (Fivecentium) is one CMU. Use the mass of a nickel to calculate the mass of a half dollar (Halfdollium), quarter (Quarterium), dime (Dimeium), pre-1982 pennies (Pre-82 Pennium), post-1982 (Post-82 Pennium). Again, show all calculations, and record all data in a data table.
5- Determine the average mass of a Pennium in CMU's using the percent abundance (from #3) of each pennium isotope (pre-82 and posst-82) and the mass of each pennium isotpope in CMU's (from #4).
*(3.03x.56)+(2.5x.44)=2.8
Questions AND Conclusions:
1- Make a statement about the average penny mass of pre-1982, post-1982, and pennies in te packet.
*New pennies, or post-1982 pennies, have more mass or are more massive than the pre-1982 pennies.
2- Explain how you derives the unit CMU.
*We used the formula given to us in the introduction. (3.03x.56)+(2.5x.44)=2.8
3- Using the idea you explained in #2 above, how did scientists obtain the Atomic Mass Unit (AMU) to measure the mass of atoms of different elements?
*They used atomic mass average base to help find all of the elements' atomic masses.
4- What is your weight in CMU's? (Remember 1lb=2.205Kg),
*.00635lb
5- Write a statement that compares what you did in this lab to what scientists have done to find the average atomic masses of the elements.
*Scientist have used the same method with Hydrogen as the smallest form of measurement to help find the atomic masses of the rest of the elements.
