We Use Soap to Clean Ourselves Better Than We Could

question 28

Multiple Choice

We use soap to clean ourselves better than we could with water alone.Soaps contain phospholipids that are responsible for the cleansing action.Which of the following statements is the most likely explanation for how soaps work?

• A) Phospholipids are ions and therefore mix with both the water and oily dirt.
• B) Phospholipids are completely hydrophilic and, therefore, oily dirt takes the place of the phospholipid molecules that would be dissolved in the rinse water.
• C) The phospholipid tail attaches to the oily dirt, while the phospholipid head interacts with the rinse water and carries the dirt (and soap) away with it.
• D) The nonpolar fatty acid chains that make up the heads of the phospholipid are hydrophilic, and thus are repelled by the water.

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Definitions:

Income Effect

The change in an individual's consumption resulting from a change in their real income, affecting their purchasing power.

Normal Good

A type of good for which demand increases as the income of individuals or the economy grows.

Substitution Effect

The substitution effect occurs when consumers replace more expensive items with less costly alternatives.

Income Effect

A change in the quantity demanded of a good or service as a result of a change in real income (purchasing power).