State whether the following is an example of a physical or chemical change:! 21. Burning a log: ________________________________
2 answers:
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The question is incomplete. Here is hte complete question.
The components of poison ivy and poison oak that produce the characteristic itchy rash are cathecols substituted with long-chain alkyl groups. The image is attached.
If you were exposed to poison ivy, which of the treatments below would you apply to the affected area? Justify your choice.
(a) Wash the area with cold water.
(b) Wash the area with dilute vinegar or lemon juice.
(c) Wash the area with sopa and water.
(d) Wash the area with soap, water and baking soda (sodium bicarbonate)
Answer: (d) Wash the area with soap, water and baking soda.
Explanation: Alkyl is hydrophobic, which means it doesn't "mix" with water. To make it more soluble in water, soap helps to dissolve the chemical compound. As shown in the image, alkylcathecol is mildly alkaline. Baking soda is a salt that also helps dissolve it by ionizing with the -OH group, which makes it more soluble.
Although lemon juice and vinegar are acids, they are weak acids and so, won't have a strong effect on the alkylcathecol.
As said before, alkyl is hydrophobic, so plain water won't affect in any way the cathecol.
