2.3 Chemical Properties and Reactions

Chemical Properties and Reactions

Draw a Conclusion

Thinking Strategy

In this case, you are being asked a cause-effect question. The question gave you the effect: Teflon’s ability to repel grease and food. It asked you for the cause. What characteristic of Teflon causes it to repel matter? To find the answer, you need to reread the passage carefully, looking for the answer to the question.

Strategy Suggestions

When you are asked to draw a conclusion, your first step is to analyze the question or break down information into parts and examine the relationships among those parts. You may have to draw a logical conclusion based on the evidence in the passage or graphic. You may have to determine the cause or effect of an event. Or you may have to figure out how two items, processes, or ideas are alike or how they are different.

EXAMPLE

Teflon, a type of plastic, has been used to line frying pans for years. Its slippery surface repels grease and food so they don’t stick to the pan. Recently, chemists and textile designers teamed up to use Teflon on fabrics. Coating fibers with Teflon protects fabrics from greasy stains.You can spill food on a Teflon-treated tie or shirt and not have to have it dry cleaned. 

What causes Teflon to repel grease and food?

A. It acts like a detergent to remove grease and food from pans and fabrics.
B. It has a slippery surface so grease and food don’t stick to it.

The correct answer B. It has a slippery surface so grease and food don’t stick to it. According to the passage, the slippery surface of Teflon causes grease and food to be repelled.

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