Elements, Mixtures, And Compounds:

Name:______

Pyrite Lab

Objective: (8.5E) investigate how evidence of chemical reactions indicate that new substances with different properties are formed

Purpose: To contrast the properties of two elements, iron and sulfur, with a new substance made from those elements.

In this lab we will investigate three essential questions: 1. How are the properties of individual elements affected when those elements are combined in a mixture?

2. How do the properties of elements change when they form a compound?

3. Is there a difference between a mixture of two elements and a compound formed from those same two elements? If there is a difference, what causes it?

Materials: Triple-Beam Balance Forceps Spoon Bunsen Burner Matches Sulfur Powder Iron Powder Hand Lens Test-Tube Beaker Magnet Safety Goggles 2 (½ sheets) white paper Test Tube Clamp Stop Watch

SAFETY: Before doing any part of the following activities, put on your safety goggles. KEEP them on for the duration of the activity.

Procedures: For each step, record all of your observations in the data table.

1. Place paper on triple beam balance to find its mass. Re-set scale to zero. Measure 4g of sulfur powder.

2. Use your hand lens to observe the color, particle size, and shape of the sulfur. Record your observations in your data table.

3. One scientist should carefully hold the paper containing the sulfur powder while another scientist moves the magnet under the paper to see if the magnet has any effect on the sulfur. Record your observations on the data table. Carefully set aside the paper that contains the sulfur.

4. Place another sheet of paper on the triple beam balance to find its mass. Reset scale to zero. Measure out 7g of iron powder.

5. Use your hand lens to observe the color, particle size, and shape of the iron powder. Record your observations on the data table.

DO NOT PUT THE MAGNET INTO THE IRON POWDER. 6. Very carefully, have one scientist hold the paper while another moves the magnet UNDER THE PAPER to see if the magnet has an effect on the iron.

7. Mix the iron and sulfur together on one piece of paper. Use your spoon to stir the mixture and mash it down until it is uniform throughout. Use the hand lens to observe the color, shape, and size of the particles. Next test the mixture to see if it is magnetic by moving the magnet under the paper. Record your observations.

8. Fill your beaker halfway with cold water.

9. Carefully pour the iron/sulfur combination into your test tube.

10. Light the Bunsen burner.

11. Using your test tube clamp, heat the test tube over the flame. Make sure to point the mouth of the test tube away from you (and others). Heat the mixture for about 4-5 minutes. Move the test tube around in the flame so that all of the contents are evenly heated. Take careful observations.

12. After 4-5 minutes, or when you see no further changes occurring in the test tube, shut off the burner. Immediately put the test tube into the beaker of water. The test tube should break. Raise your hand and Mrs. Gaffney will come to your table to remove the new substance that was created.

13. Using the forceps, hand lens, and magnet examine the new substance that was created. Record your observations.

Data Table Physical Sulfur Iron Iron-Sulfur Iron-Sulfur Properties Combination Combination Before Heat After Heat Color

Shape of Particles

Size of Particles (small, medium, large) Effect of Magnet (Magnetic or Not Magnetic) Observations What happened when I observed that… the Sulfur and Iron were heated? Be Specific!

Analysis and Conclusion

1. When you combined the iron and sulfur did you create a mixture or a compound? How do you know? ______

2. How did heating the iron and sulfur affect them? ______

3. How did the properties of the iron-sulfur combination change after it was heated? (Particle size, Magnetism, Color) Compare the new substance to both the sulfur alone and the iron alone. What changed? ______

4. Did a chemical change occur? Use your observations to justify your response. What were the signs that a chemical change occurred? ______

5. The compound you have formed is called Iron Sulfide. Sometimes it is called Pyrite or fool’s gold. The

chemical equation for the reaction is: Fe + S2  FeS2 Is this equation balanced? Show your work. (count the atoms on the reactant side and on the product side)

6. The element sodium reacts explosively with water, and the element chlorine is a yellowish-green poisonous gas. When they are chemically combined they form nonexplosive, nonpoisonous table salt. Explain how this is possible. ______

7. According to the Law of Conservation of Mass, during a chemical reaction, matter cannot be created nor destroyed; therefore if you begin your experiment with 4g of Sulfur and 7g of Iron (your reactants) what will the mass of your product be? (Show your work)