CHMA10H3 Lecture Notes - Lecture 13: Vapor Pressure, Motor Oil, Viscosity

• School: UTSC
• Department: Chemistry
• Course: CHMA10H3
• Professor: Marco Zimmerde Luliis

Document Summary

Cohesive force @ liquid surface net pull into liquid interior -> increase temp = less tension cuz increase molecules kinetic energy -> easier to stretch surface. Viscosity: resistance of liquid to flow - 1p = 1 g/ cm-s -> h2o = 1 cp. Sae scale - higher rating = more viscous -> polymer ch shape base on temp i. e. cold = coiled = x add viscosity vs hot = elongated = more viscous (factor) More spherical = lower viscosity cuz molecules roll more easily & less surface contact: increase temp = lower viscosity cuz increase molecules kinetic energy = easier to overcome force. Capillary action: narrower tube = higher raise due to 1. Adhesive force attracting outer liquid & tube surface. Faster vaporisation: higher temp, larger sa, weaker attractive force. Heat of vaporisation (delta hvap): heat energy required to vaporise 1 mol of liquid -> always endothermic/ +ve.