A tire of an automobile has a gauge pressure of 30 psi at the top of a mountain,and the air temperature inside the tire is 300 K.The atmospheric pressure at the top of the mountain is 0.7 atm.The car is driven down to sea level,where the atmospheric pressure is 1.0 atm,and the air inside the tire is heated to 350 K.At sea level,assuming no leaks,the gauge pressure of the tire will be
A)lower.
B)higher.
C)the same.

Question

Quizplus · Accepted Answer

According to the ideal gas law, PV = nRT, the gauge pressure inside the tire is directly proportional to the temperature and number of moles of gas inside the tire. When the car drives down to sea level, the atmospheric pressure outside the tire increases from 0.7 atm to 1.0 atm, but the gauge pressure inside the tire does not change because there are no leaks. As the air temperature inside the tire increases from 300 K to 350 K, the gauge pressure inside the tire will increase proportionally. However, since the atmospheric pressure outside the tire is now higher than it was at the top of the mountain, the net gauge pressure inside the tire will decrease. Therefore, the best choice is A) lower.

A Tire of an Automobile Has a Gauge Pressure of 30