Equilibrium Constant

Introduction

Reactants react to form products, during the chemical reaction. However reactions are reversible so the rate of reaction increases, concentration of products build up. When the rate of the forward reaction it happens and the reserve's reaction are equal it's called equilibrium when it happens. The reactants are being used up in the forward reaction at the same rate as they are being reformed in the reverse reaction and so the overall concentration of reactants and products remains constant. The purpose of this experiment is that the reaction between iron(III) and thiocyanic acid will be studied and the equilibrium constant for the reaction determined. To do this experiment we will be determined the co concentration by using a spectrophotometer, which we will measure the amount of light absorbed by the red complex at 447 nm. The greater the concentration the more intense the color, and the greater the absorbance it is.

Data and Results

On data sheet

Calculations

Initial moles Fe3+ = 0.010 L x 2.00 x 10-3 M Fe(NO3)3 = 2.0 x 10-5 moles Fe3+ Initial moles

HSCN = 0.010 L x 2.00 x 10-3 M HSCN = 2.0 x 10-5 moles HSCN

Equilibrium moles FeSCN2+ = 0.020 L x 1.50 x 10-4 M = 3.0 x 10-6 moles FeSCN2+

ICE diagram

Dissucssion

In this experiment our data seems accurate throughout the experiment. For each solution we filled 2.0, 4.0, 6.0, and 8.0 ml of 2.00 x 10-3 M HSCN to 100 ml with 0.200 M Fe(NO3)3.

We use a spectrophotometer helped us determine the percent absorbance for each solution.