The Quantitative Relationship Involving Concentrations of Reactants and Products at Equilibrium

Experiment 19b

The Quantitative Relationship Involving Concentrations of Reactants and Products at Equilibrium

Nicole LeBlanc                                                                                                                  Block A

Miss Tomlinson                                                                                           March 13th, 2018

Objectives:

1. to prepare various dilutions of Fe3+ ion and to react them with SCN-
2. to measure the concentration of FeSCN2+ ion produced by means of a spectrophotometer
3. to use a spectrophotometer to discover a constant mathematical relationship among the concentrations of reactants and products at equilibrium

Materials:

Apparatus                                                              Reagents

5 test-tubes (18mm x 150mm)                                        0.200M Fe (NO3)3 (acidified)

1 graduated cylinder (25 mL)                                        0.0020m KSCN

1 graduated cylinder (10mL)

3 beakers

test-tube rack

5 spectrophotometer tubes

spectrophotometer

lab apron

safety goggles

Procedure:

Refer to pages 198-200 in Heath Chemistry Laboratory Experiments Canadian Edition.

Diagram:

n/a

Data and observations

Table 1

Calculations

1. Initial amounts for [Fe3+] and [SCN-] were calculated for each test tube.

Initial [Fe3+] in test tube A:

Initial [Fe3+] =  [pic 1]

          = 0.200M [pic 2]

          =0.100M

In all other test tubes:

Initial [Fe3+] = [pic 3]

Ex. Initial [Fe3+] test tube B:

 Initial [Fe3+] = (0.200M) [pic 4]

Initial [SCN-] = [KSCN]  [pic 5]

                   = (0.0020M) [pic 6]

                       SCN-[pic 7]