4. your older brother announces that the lid to a jar of pickles from the refrigerator

is "impossible" to loosen. you take the jar, hold the lid under the hot water from

your sink's faucet for a few seconds, and calmly open the jar. your brother, when

faced with this blow to his pride, claims that he loosened it for you. what

knowledge of materials have you applied in this situation that really explains

how you were able to open the lid?

Explanation:

As the pickle jar was placed inside the refrigerator so, due to the decrease in temperature of the refrigerator the lid faced contraction in size.

As a result, it became tightly fitted over the mouth of the jar.

But when the lid was held under the hot water from your sink's faucet for a few seconds, then it undergoes a thermal expansion.

As a result, size of lid expanded as compared to the size of mouth of the jar. Hence, the lid is able to be opened up.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.