CHEM 110 Lecture 11: Sept 28/18

• School: McGill University
• Department: Chemistry
• Course: CHEM 110
• Professor: Laura Pavelka

Document Summary

H-bonding in water gives it high boiling point same with nh3. Enhancing dipole moment for polar molecule by nearby electric field. Electric field induces distortion in electron cloud. How easily can the electron cloud be distorted. Cations: lower polarizability than atoms (can polarize an electron cloud) Only intermolecular force for non polar molecules. When close, they can induce an instantaneous dipole. At lower temperatures molecules are closer together, dispersion forces increase. Molecular shape: more contact = more dispersion forces. 1,2-dimethylpropane vs pentane pentane has higher b. p. (it"s flatter) Interior molecule attracted by other molecules on all sides. Surface molecule net downward attraction, attracted below and on sides. Attraction of surface particles by interior (bulk), which minimizes surface area. Surface tension, interior molecules attempt to stretch sa, surface ones shrink it. Adhesive forces between the molecules and vessel (surface) Meniscus: concave in water, convex in mercury (only liquid metal fun)