In: Chemistry
Test tubes 1-8 contain the following amounts of 0.05M [KI] and 0.002M [I2]. The absorbance of the solutions were then measured at a wavelength of 430nm. Calculate the final [I2].
Test Tube | 0.05 M KI (mL) | 0.002M I2 (mL) | Final [I2] | Absorbance |
1 | 10 | 0 | 0.0 | |
2 | 8 | 2 | 0.369 | |
3 | 6 | 4 | 0.631 | |
4 | 4 | 6 | 0.781 | |
5 | 3 | 7 | 0.847 | |
6 | 2 | 8 | 0.914 | |
7 | 1 | 9 | 0.966 | |
8 | 0 | 10 | 1.023 |
To calculate final I2 concentration, the following formula will be used:
M1V1 = M2V2
M1 = molarity of I2 initially = 0.002 M
V1 = volume of 0.002 M I2 used (given in table)
M2 = final concentration of I2 (to be found out)
V2 = final volume. In all the cases, it is 10 ml, which is made by mixing KI and I2.
For example in test tube 1,
M1V1 = M2V2
0.002*0 = M2*10
M2 = 0 M
Similarly other concentrations can be calculated.
Test Tube | 0.05 M KI (mL) | 0.002M I2 (mL) | Final [I2] | Absorbance |
1 | 10 | 0 | 0 | 0.0 |
2 | 8 | 2 | 0.0004 | 0.369 |
3 | 6 | 4 | 0.0008 | 0.631 |
4 | 4 | 6 | 0.0012 | 0.781 |
5 | 3 | 7 | 0.0014 | 0.847 |
6 | 2 | 8 | 0.0016 | 0.914 |
7 | 1 | 9 | 0.0018 | 0.966 |
8 | 0 | 10 | 0.0020 | 1.023 |