CHEM 120 Lecture 3: January 15 2019: Lecture 3: Gases Cont’d

• School: McGill University
• Department: Chemistry
• Course: CHEM 120
• Professor: Laura Pavelka, Samuel Sewall, Pallavi Sirjoosingh

Document Summary

Large number of particles (gas molecules) follow newtonian motion. Particles are separated by a large distance. No kinetic energy is lost - is conserved. P = (n/3v)mu2 -> pv = nrt = nmu2 -> t = (namu2)/r = (na/r)( mu2. (u2) = urms = (3rt/nam) = (3rt/m) 1/2. Most molecules have average speeds while some have very low or very high. Uav = average speed which is higher than um. Urms = root mean square which is higher than uav. Square all values and add them up. Experimental observations show that gases do not always follow the ideal gas law. Experimental measurements show gases do not always follow ideal gas law. We assumed that all the gas molecules do not take up any volumes -> are point charges. Taking into account the volumes occupied by the molecules. We assumed that there are no intermolecular forces between molecules. Molecules do have intermolecular forces, especially when brought close together.