01:160:161 Lecture Notes - Lecture 5: Collision Frequency, Collision Theory, Rate Equation
19 Feb 2016
School
Department
Course
Professor
Document Summary
First order reactions - equal fractions in equal time. Logistic notes - 2015 exams and formula sheet now available in resources on sakai. The rate law shows the relationship between rate and concentration. Today we will see that the rate constant will change with temperature. Higher temperature - more movement, so molecules hit more frequently, but, more importantly, they hit with more energy! Average velocity of a molecule (gas) is given by: Which is the root-mean square or average velocity. Comparing a molecule at two different temperatures, the ratio of the average speeds is equal to. If the two temperatures are 308k and 298k, the molecules move about 1. 017% faster, meaning a relatively small increase in collision frequency - but this will have a big difference on the amount of energy the collisions will carry. Temperature dependence can be expressed using the arrhenius equation: The exponential part of the equation has no units. k= rate.
