Chemistry 1302A/B Lecture Notes - Lecture 4: Molar Mass, Jmol, Joule

• School: Western University
• Department: Chemistry
• Course: Chemistry 1302A/B
• Professor: Keith Griffiths

Document Summary

Effusion: the ow of gas molecules through tiny openings (micrometers) Lighter molecules effuse more rapidly than heavier ones and make collisions with the holes. The rate of effusion of a gas is inversely proportional to the square root of its molar mass. Rate of effusion off gas a = ngasa sqrt ( mmgasa ) Rate of effusion off gas b ngasb mmgasb. Emerging gas in more enricher in the lighter component. 238uf6: mm = 352. 05 sqrt( 352. 05/349. 04) = 1. 0043. O2 effuses for 5 minutes p = 3. 0 kpa. Unknown gas effuses for 10 minutes p = 3. 0 kpa. The unknown gas is heavier the the o2. Pressure reaches the same value in half the time for o2 effusion of unknown is slower. Runaway reaction reactions can heat & speed up exponentially. System: the part of the universe we are studying; usually the chemical reaction. Heat always ows from warmer object colder object.