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Introductory Physical Science:

Heating Copper and Sulfur

 

 

Weíre Group 3 from Period 4 IPS: Jacquelyn, Abby, Tori, Lilli, Aaron, and Bryce. Our lab, Lab 2.5 in the IPS book, is heating copper and sulfur, which has proved to be incredibly interesting.

 

To see the video of our experiment, click here.

 

So, before we begin the experiment, we need a couple safety precautions:

Wear protective gloves!

Wear safety goggles!

 

This lab can be dangerous if not performed correctly, so make sure to wear all the correct gear and follow the procedure exactly as it is written--these are things we also had to keep in mind when performing the experiment.

 

So first off, our scientific question:

 

How does the mass of copper and sulfur change when the substances are heated together?

 

Our hypothesis:

 

If the copper and sulfur are combined by the process of heating, then the mass of the copper and sulfur will increase due to the chemical bondage of the two substances by heating.

Variables:

 

Independent Variable:

Temperature of substances

 

Dependent Variable:

Mass of substances

 

Constants:

Type of substance, equal ratio between substances

 

Materials:

 

      Safety goggles (1 pair per person)

      Granular copper (2g)

      Sulfur (1g)

      Burner (1)

      Test tube (1)

      Glass rod (1) (optional)

      Rubber sheet (1)

      Rubber band (1)

      Digital Scale (1)

      Rubber Gloves (1 pair per person)

      Peg Board (1)

      Peg Screw (1)

      Rubber Tube (1)

      Paper (1)

 

 

 

Procedure:

 

1.     Gather materials.

2.     Put on goggles and rubber gloves.

3.     Put 2 grams of granular copper and 1 gram of sulfur into the test tube. Note: Do NOT use the copper dust/powder.

4.     Mix with the glass rod or shake gently.

5.     Attach rubber sheet to the end of the test tube and hold in place with a rubber band. Caution: Make sure that the rubber sheet is tightly secured onto end of test tube.

6.     Record the total mass (w/ rubber sheet, rubber band, test tube, etc.)

7.     Place the test tube above the burner.

8.     Heat mixture until it starts to glow, then remove immediately. Note: Do NOT touch the test tube until it is completely cool.

9.     Record the mass again.

10.                        Clean up any sulfur or copper that spilled, and your lab area.

 

The copper and sulfur combined together to create Copper Sulfide, or Cu2S.

 

The chemical equation of this experiment was 2Cu + S → Cu2S, and we needed activation energy in order for our chemical reaction to take place--hence the burner.

 

 

Again, see it in action here.

 

Data:

 

Change In Mass (g)

 

 

Trial 1

Trial 2

Trial 3

Trial 4

Trial 5

 

Before Heating (g)

After Heating (g)

Before Heating (g)

After Heating (g)

Before Heating (g)

After Heating (g)

Before Heating (g)

After Heating (g)

Before Heating (g)

After Heating (g)

Tori & Lilli

29.9

29.9

29.9

29.9

28.0

28.0

32.6

32.5

27.6

27.6

Bryce & Aaron

28.9

28.7

32.2

32.2

27.4

27.4

29.4

29.8

27.7

27.6

Abby & Jackie

27.2

27.2

40.0

40.0

28.0

28.0

30.0

29.9

27.6

27.6

 

Graph:

 

 

 

Conclusion:

 

Our hypothesis--that the copper and sulfur are combined by the process of heating then the mass of the copper and sulfur will increase due to the chemical bondage of the two substances by heating--was shown to be incorrect.The mass of the copper and the sulfur barely changed or didnít change altogether, as shown by 10 of the 15 trials. However, the other 5 trials showed some change, though very little, and even that was due to operational errors by the conductors. Overall, our group is confident in our conclusions because we conducted the experiment several times, and the results are incredibly similar to further solidify our data.

 

Error Analysis:

 

One source of error was the sensitivity of the scale. For example, measuring exactly 1.0 or 2.0 grams on the scale every time was difficult due to the sensitivity of the scale being to the tenth. The last digit on the scale is a rounded value, introducing imprecision to our values.Another source of error was the inability to completely control the amount of time in which the microburner was heating the copper and sulfur. Each trial was not conducted simultaneously with the total time differing by 3 seconds to 15 seconds. It is also possible that the rubber sheet responsible for containing any gas let some gas out of the test tube. This would result in the mass after the reaction being less than the mass before. With these sources of error in mind, our data isnít 100% reliable; however, our group conducted 15 trials, and all the data was relatively similar, with the difference of results being a maximum of .4 grams and we are confident those differences are accounted for.

 

 

 

 

Our group had an unusual amount of fun wearing all the correct equipment.

 

 

 

 

The mixture after the procedure.

 

††††† †††††

 

 

The copper and sulfur during the procedure††

 

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At the end of the experiment, we wanted to break open the test tubes to see what our mixture ended up looking like. Which--though very entertaining--was also incredibly interesting.

 

The Copper Sulfide [Cu2S] ended up being very brittle, and it fell apart quite easily. It appeared to be black in color with speckles of leftover dots of yellow sulfur. They ranged in size depending on how well the specimens stuck together [as shown in the pictures above].

 

Overall, it was an interesting experiment that taught us about chemical reactions; also, it gave us experience with semi-dangerous procedures in the lab, and we learned a lot about chemical reactions.†††††