"PENNIUM" LAB

OBJECTIVE:


You will investigate the concept of atomic mass and how it was derived. You will also develop your own unit of measure, the 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) 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 post 1982
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.

QUESTIONS

         PART I

1. Does each penny have the same mass?
2. Can you identify two "penny isotopes" based on masses of the pennies? Explain.
3. What does your data tell you about the relationship between mass of a penny and date of a penny. Make generalization.

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 percentage of post-1982 and pre-1982 pennies. These should add up to 100%. This calculations is the percent abundance.
4. Choose one of your coins to make a CMU (coin mass unit). For instance, the mass of a nickel is one CMU. Then you can determine the mass of a post-penny, pre-penny, Quarter, nickel, and Dime. Record all of your 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 and post) 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 and post pennies in the packet.
2. Explain how your derived the unit "CMU".
3. Using the idea you explained in #2 above, how did scientists obtain th 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 to what scientists have done to find the average atomic masses of the elements.

Our Tables:

Coin:	Mass:	Percent Abundance:	Relative Abundance:
Pre-Penny	2.96 g	40.9%	9
Post-Penny	2.38 g	45.5%	10
Quarter	5.69 g	4.5%	1
Nickel	4.84 g	4.5%	1
Dime	2.08 g	4.5%	1

      

Type of penny:	Mass:	# Of Pennies	% Abundance
Pre-1982	5.10g	9	47.4%
Post-1982	2.71g	10	52.6%

"CANDIUM" LAB

Purpose:

• Use a Candium model to explain the concept of atomic mass
• Analyze the isotopes of Candium and calculate its atomic mass.

Materials: 

An assorted sample of Candium

A scale (ex: triple beam balance)

Procedure:

1. Obtain sample of Candium.
2. Seperate the sample into groups of different isotopes. (M&Ms, Skittles, Gobstoppers...)
3. Determine the total mass of each isotope.
4. Count the total number of each isotope. 
5. Record data and calculations in the data table, which includes 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 each isotope

Discussion:

• Define the term isotope.

Isotopes are atoms of the same element that have different masses, due to different numbers of neutrons.

• Define the difference between percent abundance and relative abundance.

Relative abundance is the number of a specific group of isotopes compared to the overall total, while percent abundance is the percent of the specific group. (relative abundance/overall total)

• How to find average mass and relative mass:

To find relative mass- average mass of group/smallest average mass of all

To find average mass- weigh the group of isotopes all together, and divide by the number of isotopes in the group.

• Why is this a model for calculating atomic mass of actual elements?

This activity is a good model for calculating atomic mass of real elements because each isotope can have a different mass, although they are atoms of the same element. Not all atoms are exactly alike, but they average to make one atomic mass.

Conclusion:

Our value for relative mass was relatively similar to the the rest of the lab groups'. Percent error did cause  all of our outcomes to vary. Our error may have come from slight differences in weighing the samples and also from the different masses of the isotopes. This lab is a good way to become familiar with the concept of averaging the masses of different isotopes to create an overall atomic mass.

Our Data Table!

Candy:	Average Mass:	Percent Abundance:	Relative Abundance:	Relative Mass:
Sixlets	.82 g	35.7%	15	1 g
M&Ms	.87 g	16.6%	7	1.06 g
Skittles	1.05 g	23.8%	10	1.28 g
Gobstoppers	169 g	23.8%	10	2.06 g

Average of all = 1.09 

Introduction to the Chemistry Lab

~Purpose:


 To become familiar with the laboratory and to make qualitative and quantitative observations about physical and chemical changes during a chemical reaction.

~Materials:

• beaker (150 or 250 ml)
• copper (II) sulfate pentahydrate - CAUTION... it is toxic! 
• scoopula
• 100ml graduated cylinder
• stirring rod
• thermometer
• small square of aluminum foil

~Procedure: 

1. Form a lab group of two or three people
2. Go to the lab station after taking appropriate safety precautions we have discussed in the safety lecture. (You must wear safety goggles and an apron.)
3. Prepare a beaker (150 or 250ml), a 100 ml graduated cylinder, a scoopula, a 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 100 ml.
4. Using the scoopula, obtain some of the copper(II) sulfate pentahydrate. (The exact amount is not important, but the scoopula should be about one quarter filled.) Place it in the beaker and stir with the stirring rod until all the solid has dissolved. 
5. Obtain the aluminum foil sample in front of you and crumple it into a loose ball. Place the aluminum ball into the copper(II) sulfate solution and stir for about 15 sec.
6. 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(II) sulfate-aluminum mixture. Stir until all of the sodium chloride is dissolved.
7. After approximately 10 min., take your beaker over to a safe container and carefully dispose of the mixture. 

Clean-up:

1. Clean your beaker thoroughly with soap and water, rinsing it last with distilled water. 
2. Make sure your lab station is clean.
3. Return all safety equipment to it's proper location.

Lab Discussion:

Did a chemical change occur after the addition of the aluminum? Explain.

Did you see a physical or chemical change after the addition of sodium chloride? Explain.

How many different states of matter did you observe? Describe what they were.

What might the red solid at the bottom of the beaker have been?

Conclusions:

After we mixed the copper (II) sulfate pentahydrate with the water, the mixture was homogeneous (the same throughout).

When we added the aluminum, however, the mixture bubbled a little bit and the mixture became cloudy and formed a precipitate, which is an indicator of a chemical change. The temperature was about the same, but the mixture was then heterogeneous.

After we added the sodium chloride, the aluminum turned black and started to bubble. Then, it formed a red solid that stuck to it. In this experiment, we observed three states of matter: a solid (the beaker, aluminum, and red precipitate); a gas (the bubbles coming from the aluminum); and a liquid (the copper(II) sulfate pentahydrate). We also observed chemical changes, which were: bubbles, formation of a precipitate, and change in color.

Indicators of Chemical Change

1. Formation of a precipitate
2. Heat transfer
3. Color change
4. Bubbles without heat

Fun Facts:


This is a model of what copper(II) sulfate looks like. I got this picture from http://commons.wikimedia.org/wiki/File:Copper(II)-sulfate-unit-cell-3D-balls.png





http://phet.colorado.edu/en/simulations/category/new
go to this link for very fun science stuff.

The Epic, Amazing, Awesome and Incredible Bubble Lab

    The purpose of this lab is to test the hypothesis that bubble-making can be affected by adding table sugar or table salt to a bubble blowing mixture.

Materials-

1. Three plastic cups

2. Liquid dish detergent

3. Measuring cup and spoons

4. Water

5. Table sugar

6. Table salt

7. Drinking straws

Procedure-

1. Label three drinking cups one, two, and three. Measure and add one teaspoon of liquid dish detergent to each cup. Use the measuring cup to add two thirds of a cup of water to each drinking cup. Then, swirl the cups to form a clear mixture.

(Wipe up any spills immediately so that no one will slip and fall.)

2. Add a half teaspoon of table sugar to cup two, and a half teaspoon of table salt to cup 3. Swirl each cup for one minute.

3. Dip the drinking straw into cup one, remove it, and blow gently into the straw to make the largest bubble you can. Practice making bubbles until you can reasonably control your bubble production. 

4. Repeat step 3 with mixtures in cups two and three.

Hypothesis: 

The mixture with the salt won't do as well, and the mixture with the sugar will be more durable.

Analyzation and Conclusion: 

The sugar mixture had bigger bubbles that were harder to pop. The control mixture made average bubbles that were well-sized, but weaker. The salt mixture could hardly produce bubbles at all. We probably should have measured the soap and water more precisely.