Tire gauges

Suppose just before taking a trip you filled your tires to 30 pounds pressure (psi lb/in2) and the temperature that day was 27°F. After the trip, you checked the pressure and found it to be 34.2 psi. Estimate the temperature in °F of the air in the tires. Assume that the tire gauge reads relative pressure, that the volume of the tires remains constant, and that the ambient pressure was 1.00 atm that day. 

The air pressure of car tires should be checked regularly for safety reasons and to prevent uneven tire wear. Find out the units of measurement on a typical tire gauge, and determine how gauge pressure relates to atmospheric pressure. 

Automobile tires are normally inflated to a pressure of 28 psi as measured by a tire gauge, (a) Express this pressure in atmospheres, (b) Assuming standard atmospheric pressure, calculate the internal pressure of the tire. 

The most familiar tire gauge is about the size and shape of a ballpoint pen. It is a convenient way to check tire pressure for proper inflation regularly. Proper inflation ensures tire maintenance and safety. 

You use a tire gauge to measure the air pressure in a bicycle tire. The gauge reads 38.5 psi. What is the absolute pressure in the tire in kilopascals ... 

A tire gauge at a gas station indicates a pressure of 29.0 psi in your tires. What is the absolute pressure in your tires in inches of mercury ... 

Look inside a tire gauge, an electric lighthulh, or a rechargeable battery to find out what makes them work. How does chemistry help you understand these simple everyday items ... 

We use various devices to measure the pressures of enclosed gases. Tire gauges, for example, measure the pressure of air in automobile and bicycle tires. In laboratories we sometimes use a manometer, which operates on a principle similar to that of a barometer, as shown in Sample Exercise 10.2. 

We have used a tire gauge and measured the air pressure inside a car dre to be 35.0 psi. What is the absolute pressure of the air inside the dre, if the car is located in (a) a dty located at sea level, (b) a city located in Colorado with an elevadon of 1500 m Express your results in both units of psi and pascals. 

Outside the laboratory, mechanical gauges are used to measure gas pressure (Fig. 4.8). A typical tire gauge is probably the most familiar. Tire gauges show the pressure above atmospheric pressure, rather than the absolute pressure measured by a manometer. Even a flat tire contains air that exerts pressure. If it did not, the entire tire would collapse, not just the bottom. The pressure of gas remaining in a flat tire is equal to atmospheric pressure. If a tire gauge shows 25 psi, that is the gauge pressure of the gas (air) in the tire. The absolute pressure is nearly 40 psi—the 25 psi shown by the gauge plus about 15 psi (1 atm = 14.69 psi) from the atmosphere. 

If more gas is added to a container of fixed volume that is already filled with a gas, the pressure increases. If some gas is removed from a container of fixed volume, the pressure decreases. For example, when more air is pumped into a tire that is already filled with air, the pressure increases (as measured by the tire gauge). If some air is released from a tire filled with air, the pressure decreases. 

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