6. Allow the washed half-strip to dry and then compare the washed half to the unwashed half. Record your observations in your data table. Staple the half-strips to a sheet of paper and label each half-strip to indicate how you treated it.

Part B: Dyeing With Treatment

7. Use the tongs to place the second fabric strip in the iron(II) sulfate solution for 25 minutes. Then use tongs to lift the strip and allow it to drain into the iron(II) sulfate solution. Wring the strip as dry as possible over the solution. CAUTION The strip will be hot. Allow it to cool before touching it. Wear plastic gloves.

8. Repeat Steps 2, 3, and 4 using the strip that you treated with iron(II) sulfate.

9. To test the strip for colorfastness, repeat Steps 5 and 6.

10. Clean up your work area and wash your hands thoroughly with warm water and soap before leaving the laboratory.

Analyze and Conclude

1. Comparing and Contrasting How did the color of the untreated strip compare with the color of the treated strip?

2. Comparing and Contrasting How did the colorfastness of the untreated strip compare to the colorfastness of the treated strip?

3. Applying Concepts Silk blouses and shirts can be purchased in many intense colors. Why do you think silk is able to hold a variety of intense dyes?

4. Drawing Conclusions How does iron(II) sulfate affect the ability of a fabric to absorb dyes? (Hint: What kind of compound is iron(II) sulfate?)

5. Predicting A care label might say Wash in cold water only. What might happen to the color of a piece of clothing with this label if you washed the clothing in hot water?

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