Determination of an Equilibrium Constant
Student: Jiahao Liang
TA: Dan Drew
* Qualitative Data
After finish preparing each required solution with diverse concentration, each of them was labeled what concentration it is. Among the first three prepared solutions and the volume of Fe3+ keeps constant, the darkest colored test tube is with the SCN- volume of 2.0mL, and the lightest one is the tube prepared by 0.5mL SCN-. However, the concentration of each combined solution was identical and did not change through the experiment with the unchanged total volume. This situation is trend in accordance with Le Chatelier’s Principle, which is saying that an additional reactant is added to the reaction at equilibrium and the forward reaction will occur at a larger rate. When keeping the volume of SCN- to be unchanged, the trends in color transition were similar as the experiment with the constant volume of Fe3+. The brightest tube was the smallest amount of volume in Fe3+ which was 1.0mL. And the darkest one was the tube with 2.0mL volume of Fe3+ and the solution with intermediate colored contained 1.0mL of Fe3+ and 1.0mL of SCN-.
In order to emphasize effect on the disturbance of a chemical reaction with the changing in temperature, three more fresh solutions in intermediate color were remade and each of them was settled in room temperature, an ice water bath and a hot water bath. The trends in color transition in a warmer water bath were also correlated to the Le Chatelier’s Principle, which is also stating that the increase in temperature will increase the rate constant of the endothermic reaction and the concentration of the product produced in this heat absorbing reaction will increases. So, the color became darker and darker when the solution was settled in a warmer environment. In the ice water bath, the color of the solution has no significant change. This variation in color of the solution was also in...