As the air molecules move through the valve they have friction as they hit the walls, and its this friction that causes it to heat up.
What are the answers choices?
Answer:
The warmer, lighter air rises, bringing cooler, heavier air to low altitudes.
Air at higher altitudes doesn't have as much air weighing down on it from above.
Explanation:
In short - air pressure is the result of the cumulative force that air molecules act on objects below them due to Earth's gravity. The higher the altitude, the less air molecules there are to act a force below them, and therefore, there's less air pressure at higher altitudes.
A moon would be the correct answer.
A strong base turns phenolphthalein pink, so the answer is (3) NaOH
