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.