Figure 1: Concentration vs Time
Table 2: Initial Rates
|Trial||Initial Rate (M/s)|
|1||1.33 x 10^-8|
|2||2.72 x 10^-8|
|3||4.60 x 10^-8|
Table 3: Determination of the reaction rate constant
|Trial||k' (Ms^-1)||[OH] M||K (s^-1)|
|1||1.33 x 10^-4||2.5 x 10^-2||0.00532|
|2||2.73 x 10^-4||5.0 x 10^-2||0.00546|
|3||4.60 x 10^-4||2.5 x 10^-2||0.0184|
1. Calculate m from the rates of Trial 1 and Trial 3.
2. Calculate n from the rates of trial 2 and trial 3.
3. Rate constants for all three trials
The purpose of this lab was to determine how fast is "fast" for a chemical reaction. he area of chemistry that deals with how quickly or slowly reactions take place is called kinetics. The rate of the reaction depends on the concentration of the reactants and can be mathematically expressed as the rate law. In this lab the concentration of the reaction was monitored in a chemical reaction using a spectroscopic method and Beer's Law. The chemical reaction was between crystal violet and OH- ions where crystal violet is a blue color and the OH- ions were colorless. The absorption is attributed to the reactant present in the solution. The "initial rate method" was be used to determine the order of reactants. This was done by measuring the initial rate of the reaction under carefully chosen conditions and then applying the rate equation under two different conditions.
The results of this lab was that it looks like the order of the reaction is a second rate reaction. The order of reaction for the crystal violet was 1.79 and the order of the reaction for OH- was 0.79. In reality the reaction should have been a first order reaction so the results obtained are not that accurate and do not reflect what should have occurred. Some possible errors that could have occurred to get these off results could have been from not mixing the solutions well enough before putting it in the red tide, not calibrating the red tide and GLX correctly and not cleaning the cuvette thoroughly before putting it in the red tide. In order to get more accurate results, all of those possible errors should be addressed to make the experiment better.