## Physics: Principles with Applications (7th Edition)

The ideal gas law, equation 13-3, says that $PV = nRT$. At fixed temperature, the pressure is proportional to the number of moles n, and inversely proportional to the volume V: $P=\frac{nRT}{V}$. Bottle B has twice the volume and only half the number of moles as Bottle A. It has one-fourth the pressure as Bottle A.