ABSTRACT
We live and breathe in the atmosphere, a sea of gas composed mostly of elemental nitrogen gas (N2), O2, and water vapor. The fundamental properties of gases determine the properties of the atmosphere. Recall that gases consist of molecules and (in the case of noble gases) atoms with large amounts of space between them. The gas molecules are in constant, rapid motion, which causes gases to exert pressure. The motion of gas molecules becomes more rapid with increasing temperature. Due to their constant motion, gas molecules move by a process called diffusion. The relationships among the amount of a gas in moles and its volume, temperature, and pressure can be calculated by the gas laws discussed in Chapter 19.
