Written by Lisa Abstract Bromothymol blue is an indicator used to detect weak acids and bases. In acidic solutions, it appears yellow, in basic solutions it is blue, and in mid pH ranges, it is green. By determining the absorbance values of solutions at all of these extremes, the equilibrium constant (Kc) of this indicator can be calculated. After taking the spectra of each the yellow, the blue and the green solutions, a Kc value of (1.2 ± 0.19) M and […]
Objective Determine the equilibrium constant Kc for the chemical reaction: Fe3+(aq) + SCN–(aq) ß à FeSCN2+(aq) Procedure 0.0020M Fe(NO3)3 (ml) 0.0020M KSCN (ml) H2O (ml) 5 2 3 5 3 2 5 4 1 5 5 0 18 (0.2M) 2 0 (1) Calibrate the colorimeter. (2) Prepare five test tubes with the designated solutions: (3) Measure each solution using the colorimeter and computer software. (4) Record an observation of the solution temperature. (5) Calculate the average equilibrium constant for the […]
