Candium
- So.... What is the Purpose of This Lab?
- And.... What Do We Need For This Exaclty?
- A Brain.... lol tee hee. I know this might be hard for some of you but.... (:
- A sample of the Canduim - (in our case, we used Everlasting Gobstoppers, Sixlets, M & M's, and Skittles)
- A triple beam balance
- A notebook and a pencil to jot down the fantasmical information that you will be given in this lab
- If your brain isn't working, might i suggest a calculator.... (don't worry, i used one, too!)
- Now, Um.... How Do We Do This?
I'm glad you asked. Here are the steps to find the atomic mass.
- Obtain the samples of Candium
- Seperate it into the correct isotopes. (All the Skittles together, all the Sixlets together etc.)
- Count the number of each isotope.
- Record the data and calculations in a data table the data table must include:
- The 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
This data table you must create should have five columns and seven rows (:
Candy Mass Average mass % Abundance Relative Ab. Relative Mass
Gobs. 21.10g 1.60g 14.8% 13 1.95 CMU
M&M's 27.00g .87g 32% 31 1.06 CMU
Sixlets 22.10g .82g 29% 27 1.00 CMU
Skittles 24.00g 1.04g 24% 23 1.26 CMU
You have passed the first lab... But wait young grasshopper... Another lab awaits....
PENNIUM LAB (:
Most elements consist of a mixture of 2 or more naturally occurring isotopes. If you don't know already, isotopes are atoms of an element that vary because they have different mass numbers, and numbers of nuetrons)
Now....pretend that you have an element called "pennium"( really it is only a bunch of pennies). Through comparing the masses of the "penny atoms" you will see how many different Pennuim isotopes are in the bag full of pennies. You will then determine the average atomic mass of Pennuim using the following equation: ( average mass of isotope #1)*(percent abundance of isotope #1)+(average mass of isotope #2)*(percent abundance of isotope #2). Wow! That is a lot!
Next, you will choose another element (five centium) to be the accepted mass standard to which all of the other atoms are compared for mass. You'll use the mass of a nickel( the fivecentuim) to determine the relative mass of Pennium, Dimeuim, quarteruim, adn Halfdollium. All relative masses will be expressed in CMU (Coin Mass Units)!
If you read all that and are still reading, you will make it through this lab!!
Objective:
- Investigate the concept of atomic mass and how it was derived
- Develop you own unit of measure (CMU) and use it to measure the relative masses of other coins
- At the end of this lab, you will be able to explain how scientists developed the system for AMU's (atomic mass units) & how it is applied to determine the relative masses of other atoms of other elements
Procedure: Part 1!
- Obtain a packet of pennies
- sort the pennies into 2 groups: pre-1982 & 1982 and newer
- measure the mass (in grams) of each stack of pennies. Record the mass of each penny stack in a data table. Count the number of pennies in each stack.
- Measure the mass in grams of a half dollar, quarter, nickel, and dime. Record these values in a data table
- Answer the questions below and then continue with part 1.
Questions: Part 1
- Does each penny have the same mass? No
- Can you identify 2 "penny isotopes" based on masses of the pennies? Explain. Yes because the pennies vary in mass -- mass numbers
- What does your data tell you about the relationship between mass of a penny and date of a penny. Make a generalization. Well... the the mass of a penny has risen since the pennies that are "pre-1982".
Coin Relative Abundance Mass
Pre-1982 10 pennies 27.50g
Post-1982 10 pennies 27.90g
Quarter 1 5.65g
Nickel 1 .65g
Dime 1 2.10g
Procedures:
- Determine the average mass of pre-1982 pennies. 2.75g
- Determine the average mass of post-1982 pennies. 2.79g
- Determine the percentage of the mass number in each group of pennies that you have. What you have just added up is the percent abundance of each group of pennies (penny isotopes). Each 50%
- Choose one of your coins to make it your CMU (coin mass unit). Let's say that the mass of a nickel is one CMU. Use the mass of the nickel to calculate the mass of the other coins. Show results in a data table.
- Determine the average mass of Pennuim in CMU's using the percent abundance of each pennuim isotope and the mass of each pennium isotope in CMUs. 2.77g
- Make a statement about the average penny mass of pre-1982, post-1982, and pennies in the packet. The average mass of the post-82 pennies to the pre-1982 was just slightly higher.
- Explain how you derived the unit "CMU". Well... You use the mass of one coin to find what the other coins were relative to it! -- Relative Abundance
- How did scientists obtain the Atomic Mass Unit to measure the mass of atoms of different elements? They compared it to other elements that they knew the atomic mass of.
- What is you weight in CMU's? If a man weighs 300 lbs. I have a .433 relative abundance compared to his weight.
- Write a statement that compares what you did in this lab to what scientists have done to find the average atomic mass of elements. I compared coins to other coins; they compared the atomic mass of elements to other elements.
Info from Part 2:
Coin Mass Relative Abundance
Nickel 4.65g 1.00 CMU
Nickel 4.65g 1.00 CMU
Quarter 5.65g 1.22 CMU
Dime 2.10g .45 CMU
Pre-82 penny 2.50g .54 CMU
Post-82 penny 3.10g .67 CMU