PRE-LAB QUESTIONS 1. The blue-black color appearing in the reaction mixture is caused by a complex between and 2. This experiment makes use of the relationship between and a reaction. in the Arrhenius equation in order to determine the of 3. a) In this experiment k (the rate constant) is proportional to the rate, but you don't measure k directly. What do you measure that is related to k? b) What is k equal to in the rate law?