Calculate the number of moles of gas in a 3.24-L basketball inflated to a total pressure of 24.3 psi at 25 °C. The total pressure is not the same as the pressure read on a pressure gauge such as the type used for checking a car or bicycle tire.

That pressure, called the gauge pressure, is the difference between the total pressure and atmospheric pressure. In this case, if atmospheric pressure is 14.7 psi, the gauge pressure would be 9.6 psi. However, for calculations involving the ideal gas law, you must use the total pressure of 24.3 psi.