Question

[Fe+3] [SCN]: of Table 2. Initial Data to Determine Keq Trial Volume Volume Total | Absorbance of Fe+3 volume KSCN(mm) (mm) (mL) hao 5.00 10.00 10.110 | 2 200 5.00 10.00 0.225 3 3.00 5.00 10.00 0.359 4 4.00 5.00 10.00 0.479 5 5.00 5.00 10.00 0.626 11.00×10 -3 2.00x104

How do I calculate [SCN-]i given that:
Stock [Fe3+] = 0.00200 M
Stock [SCN-] = 0.00200 M

Answer 1

Answer:

SCN- for trial 1

V1= initial volume=1 mL

S1=initial concentration =0.002 M

V2= Final volume =10 mL

S2= final conc. = ?

So,   V1 S1 = V2 S2

S2 = (1 mL x 0.002 M )/ 10 mL =2 x 10-4 M

similarly for trial 2

V1= initial volume=2 mL

S1=initial concentration =0.002 M

V2= Final volume =10 mL

S2= final conc. = ?

So,   V1 S1 = V2 S2

S2 = (2 mL x 0.002 M )/ 10 mL =4 x 10-4 M

similarly for trial 3

V1= initial volume=3 mL

S1=initial concentration =0.002 M

V2= Final volume =10 mL

S2= final conc. = ?

So,   V1 S1 = V2 S2

S2 = (3 mL x 0.002 M )/ 10 mL =6 x 10-4 M

similarly for trial 4

V1= initial volume=4 mL

S1=initial concentration =0.002 M

V2= Final volume =10 mL

S2= final conc. = ?

So,   V1 S1 = V2 S2

S2 = (4 mL x 0.002 M )/ 10 mL =8 x 10-4 M

similarly for trial 5

V1= initial volume=5 mL

S1=initial concentration =0.002 M

V2= Final volume =10 mL

S2= final conc. = ?

So,   V1 S1 = V2 S2

S2 = (5 mL x 0.002 M )/ 10 mL =10 x 10-4 M