Candium!!

Purpose

•  To use a Candium model to explain the concept of atomic mass. 
•  To analyze the isotope of Candium and calculate its atomic mass.

Materials

• Sample of Candium
• Triple Beam Balance

Procedures

1. Obtain sample of Candium
2. Separate it into its 4 isotopes
3. Determine the total mass for each isotope
4. Count of the numbers of each isotope 
5. Record data and calculations in the data table 

     create a data table that has the following:

• 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

     Your Date Table Should Have Five Columns And Seven Rows!!

Discussion:

1. Summarize what you did.
2. Define the term isotope.
3. Explain the difference between percent abundance and relative abundance. (Hint: What is the result when you total the individual percent abundance values for each isotope? What is the result when you total the individual relative abundance values for each isotope?)
4. Compare the total values for rows 3 and 6 in the data table.  How does the average mass differ from the relative mass?
5. Compare your value for relative mass to that of the class. 
6. Comment on your percent error, sources of error in the activity, and provide suggestions for improvement.
7. comment on how the activity is a model for calculating atomic mass of real elements.

Conclusion:  Personal commentary on the lab activity. 

Pennium

Intro-  Most elements consist of two or more naturally occurring isotopes.  (Atoms of an element that vary because they have different mass numbers, numbers of neutrons) Different isotopes of an element have different relative atomic masses due to the different numbers of neutrons in the nucleus. 
in this lab you are pretending that you have an element called Pennium, you will be given a bag of this element.  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 using the following equation:  (average mass of isotope 1)(percent abundance of isotope 1)+(average mass of isotope 2)(percent abundance of isotope 2). Next you will choose another element (Fivecentium) to be the accepted mass standard to which all other atoms are compared for mass.  You'll use the mass of a nickel to determine the relative mass of Pennium, Dimeium, and Quarterium.   All relative masses will be expressed in CMU (Coin Mass Units).


Objectives-  In this lab 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 I
     1.  Obtain a packet of pennies.
     2.  Sort the pennies into two groups: pre 1982 and 1982 and newer. 
     3.  Measure the mass (in grams) of each stack of pennies, record the mass (in grams) of each penny stack in a data table.  Count the number of pennies in each stack.  
     4.  Measure the mass (in grams) of a quarter, nickel, and dime.  Record these values in a data table. 
     5.  Answer the questions below and then continue with Part II. 


                                                                           Pennies
                                               Pre (9)                                           Post (8)
Mass (group)                     27.9 grams                                       10.98 grams


Average mass (one)           2.9 grams                                          2.5 grams


to be cont... 


Part I Questions
1.  Does each penny have the same mass?  A:  sure did
2.  Can you identify two penny isotopes based on masses of the pennies? Explain.  A:  Not unless you knew which time period (post or pre) had the heavier pennies. 
3.  What does your data tell you about the relationship between mass of a penny and date of a penny.  Make a generalization.   A: the newer they pennies are, the less the mass is.  


Procedures
Part II
1. Determine the average mass of pre- 1982 pennies.  (Record average)
2. Determine the average mass of post- 1982 pennies.  (Record average)
3. Determine the percentage of your pennies that are 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).
4. Choose one of your coins to make a CMU (coin mass unit).  The mass of a nickel (Fivecentium) is one CMU.  Use the mass of a nickel to calculate the mass of a quarter (Quarterium), dime (Dimium), pre-82 (Pre-82 Pennium), post-82 pennies (Post-82 Pennium).  Show all calculations, and record all data in a data table. 
5. Determine the average mass of Pennium in CMU's using the percent abundance (from #3) of each pennium isotope (pre-82 and post-82) and the mass of each pennium isotope in CMU's (from #4).  


Questions and Conclusions
Part II
1. Make a statement about the average penny mass of pre-82, post-82, and pennies in the packet. 
2. Explain how you derived the unit "CMU".
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?
4. What is your weight in CMU's?  (Remember 1lb= 2.205 Kg)
5. Write a statement that compares what you did in this lab o what scientists have done to find the average atomic masses of the elements. 

Copper Foil

Purpose- The purpose of the lab was to become more familiar with the lab. Also to make qualitative and quantitative observation about physical and chemical changes during a chemical reaction.
Materials- Beaker (150-250)
Copper(II) sulfate pentahydrate- caution, toxic substance
Scoopula
100ml graduated cylinder
Stirring rod
Thermometer
Small square of aluminum foil
Procedure- This lab is unique in that it serves both as an introduction to a laboratory environment and as a review. It demonstrates the terms and concepts we have learned recently learned in the lecture. Thus, as you read and follow the procedure, be sure to answer all the questions that are posed to you in the spaces provided on your paper.


1. Form a group of TWO OR THREE PEOPLE. Go to your lab station after taking all appropriate safty precautions that we discussed in the safety lecture. (YOU MUST WEAR SAFETY GOGGLES AND APRON.)


 QUESTIONS AND ANSWERS


2. You will find in front of the beakers at your station, the 100 ml graduated cylinder, a scoopula, the thermometer, some aluminum foil, and a container holding some cupric sulfate pentahydrate. Go to the appropriate source and add some water in your beaker. The exact amount is not important, although it should be between 75 and 100ml. Make sure you write down how much water you put in the beaker though.
     QUESTION- Make ONE qualitative and TWO quantitative observations of a physical property of the water in the space below. Be sure to make it clearly distinguish which is which.


      Qualitative- The water is clear.
      
      Quantitative- 1. The water is 79 ml
                             2. The temperature is 22 degrees Celsius


3.  Now, using the scoopula, obtain some of the copper(II) sulfate pentahydrate. Again the exact amount is unimportant, but your scoopula should be about one quarter filled with the solid ( Ask the teacher if you need help with anything.) Place the copper into the beaker and stir with the stirring rod until all the solids have dissolved.
    QUESTION- You have just made a mixture of CUSO4 in water. Is this mixture homogeneous or heterogeneous? Explain.


     Heterogeneous because the water turned blue from the copper solids.


4. Obtain the aluminum foil sample in front of you and crumple it up into a loose ball. Then place the ball carefully into the mixture and stir gently for 15 seconds. Write down a detailed observations of everything you see in the space below. At least one of the observations should be quantitative.


     OBSERVATIONS AFTER ADDITION OF ALUMINUM-
  
    Nothing really happened the foil kinda bubbled but other than that the quantitative is that the volume of the beaker rose up more so its 80.


    Did a chemical change occur ethe additional of the aluminum? Explain.
Yes there was a chemical change.  The color of the water changed to a deeper blue, and the temperature changed a little as well.


5. Make sure your scoopula is clean (rinse with tap water and dry with a paper towel if not) and obtain a large scoop of sodium chloride from the labeled container  Add the NaCl to the beaker containing the copper (H) sulfate - aluminum mixture.  Stir until all of the sodium chloride is dissolved and make detailed observations of everything you see in the space below:  Again at least one of the observations should be quantitative.
OBSERVATIONS AFTER ADDITION OF SODIUM CHLORIDE: 
- It turned into a heterogeneous mixture
- Black chunks floating, it sticks to the alluminum
- when chunks are stuck to the alluminum, they appear to be red


Did you just see a physical change or a chemical change? Explain.
We saw a physical change; the black chunks are still floating in the solution.


How many different states of matter do you observe? Describe, from your observations, what they are.  Which do you see in the beaker right now?
We see 2 different states.  Liquid and the chunks of black and red.
we see both liquid and solid


Any idea what the red solid is that dropped to the bottom of the beaker?
Copper


6.  After approximately 10 minutes, take your beaker over to the large funnel and beaker and slowly decant (pour) your mixture into the beaker.  The instructor will show you a way to do this that will insure that all the liquid ends up in the funnel.  Then clean your beaker thoroughly with soap and tap water and then a final rinse with distilled water.  Make sure our lab station is clean, return all safety equipment to its proper location, then return to your desk.


DISCUSSION: You have just observed a chemical reaction between copper ion and aluminum, which produced copper metal, hydrogen gas, and aluminum ions.  During the course of the reaction, you should have made several different observations that are all indicators that a chemical change is occurring.  From the discussion in the class list the indicators below:
                                                   Indicators of a Chemical Reaction
1)  Bubbles form without adding heat
2)  Heat is produced
3)  Precipitate forms
4)  Change of color