Physical Chemistry IV (Electrochemistry and Photochemistry)

GENERAL OBJECTIVES:

1. Understand the behaviours of ions in solution

2. Understand the nature of electrochemical cells

3.Understand the phenomenon of ion transport and molecular diffusion.

4.Understand photochemical reactions

1.1 Define the following - activity, activity coefficient and the mean activity coefficient of ions in solution.

1.2 Describe the ionic atmosphere.

1.3 State the role of ionic atmosphere in determining the value of the mean activity coefficient.

1.4 State the form of a shielded coulomb potential.

1.5 Define ionic strength.

1.6 State and derive the DebyeHuckel limiting law for the mean activity coefficient.

1.7 Explain how the DebyeHuckel limiting law may be extended to more concentrated solutions.

1.8 Define the electrochemical potential of an ion.

1.9 Derive an expression for the potential difference across an interface in terms of the standard potential difference and the activity of ions.

1.10 Derive an expression for the potential difference across a gas/inert metal electrode.

1.11 Derive an expression for the potential difference across a metal/insoluble salt/ion electrode.

1.12 Describe the construction of metal/insoluble salt/ion electrode.

1.13 Derive an expression for the potential difference at a redox electrode (oxidation potential).

1.14 Obtain Ecell from data using the expression in 1.14 above.

1.15 Describe the formation of a liquid junction potential.

1.16 Derive an expression for the potential difference across a membrane.

1.17 Describe the construction of a cell with a liquid junction and a cell without a liquid junction.

2.1 Define thermodynamic reversibility of an electrochemical cell.

2.2 Define electrode potential and describe the sign convention.

2.3 Relate the e.m.f of a cell to the spontaneous direction of change of the cell reaction.

2.4 Define the term standard e.m.f.

2.5 Derive the Nernst equation for the concentration dependence of the e.m.f. of a cell.

2.6 Relate the standard e.m.f. to the equilibrium constant of the cell reaction.

2.7 Describe the method of measuring standard electrode potentials.

2.8 Describe the measurement of activity coefficients.

2.9 Relate the temperature dependence of the e.m.f. to the entropy of a cell reaction.

2.10 Define solubility product and deduce its value from e.m.f. data.

2.11 Describe the electrochemical basis of a potentiometric titration.

2.12 List the applications of electrochemistry e.g. corrosion, protection etc.

3.1 Define conductivity and molar conductivity of solutions.

3.2 Explain how conductivity and molar conductivity of solutions can be measured.

3.3 State Kohlransch’s law of independent migration of ions.

3.4 Calculate the molar conductivity of a solution using

3.4 above.

3.5 State Oswald’s dilution law.

3.6 Use 3.6 to calculate the molar conductivity of weak electrolytes using Oswald’s dilution law.

3.7 Define the drift velocity and the mobility of ions.

3.8 Relate molar conductivity to ion mobility.

3.9 Define the transport number of an ion.

3.10 3. List the factors that affect the mobility of ions.

3.11 State the basis of the Debye-Huckel - Onsager equation.

3.12 Define a thermodynamic force.

3.13 Derive the diffusion equation and use it to describe the diffusion of a solute into a solvent

4.1 Explain the influence of light on chemical system.

4.2 Define quantum yield efficiency.

4.3 Calculate the quantum yield efficiency of a photochemical reaction from a given data.

4.4 Derive rate laws for a given photochemical reaction.

4.5 Define photo stationary state.

4.6 Define fluorescence, phosphorescence and chemiluminiscence.

4.7 State the importance of photosensitized reactions.