lab report for monomeils

Goal(s): To study the effect of concentration on the rate of a reaction, and to find the order of the reaction in each reactant and write a rate equation.

Background Theory: Chemical reactions occur at different rates that ultimately depend on their concentration, the temperature, the usage of catalysts, the nature of reactants, like the surface area of the particles. Concentration, for instance, increases the number of molecules or particles in a certain volume, so collisions will become more frequent. Temperature increases the rate by making particles move faster, creating more rapid collisions in a certain allotted time frame. Moreover, when the surface area of molecules increases, the rate will increase. This is due to the fact that it will increase the chance of collisions taking place. Finally, catalysts will change the mechanism, speeding up the rate of the reaction, while inhibitors will oppositely decrease the rate. The similarities between each of these factors in the increase of rate is that they all happen to increase (or decrease in the case of the inhibitor) the number of collisions. Overall, the rate of the given reaction will depend on the frequency with which the reacting particles will collide. In this experiment, the concentration of one reactant will differ from its concentration in other trials, but all the other factors will remain the same. A group of clock reactions will be used to determine the effect of concentration on reaction rate. The reactions include: 1.) NaHSO3 + H2SO4  H2SO3 + NaHSO4 *this reaction occurs quickly and is common to miss 2.) KIO3 + 3H2SO3  KI + 3H2SO4
3.) KIO3 + 3H2SO4 + 5KI  3K2SO4+3H20 +3I2 4.) I2 + H2SO3 + H20  H2SO4 + 2H + 2I 5.) I2 + starch  starch I2 (blue-black color) Mathematically, we can use the Molarity formula to solve for the molarity of each solute (KI03 and NAHSO3) in order to later solve for the second concentrations of each using the M1V1=M2V2 formula. A graph will then be created, plotting the time of the reaction versus the concentration of the varied reactant.

Procedure:
1. First, using our large beaker, we filled it with KIO3 –potassium iodate.
2. Our lab group then filled the 4 125 ml Erlenmeyer flasks with different volumes of water, in order of reaction: 0.0, 5.0, 10.0, 15.0, and 20.1 ml. (measuring with a graduated cylinder)
3. Using a stopwatch, we then poured a certain volume of KIO3 into a large beaker and then into each one separately, in order of reaction: 30.0, 25.0, 20.0, 15.0, and 10.0 ml.
4. For each flask & reaction, our lab group began timing as soon as the KIO3 hit the water, and stopped the watch exactly when the solution began to turn blue.
5. We wrote down our times in the data table listed below.
a. [NaHS03] was kept constant and [K