Diploma Food Technology

Physical Chemistry

Lesson Thirteen

1) Rate of Reactions

a) Fist Order reactions

b) Second Order Reactions

c) Equilibrium

d) Equilibrium constant

e) Mass Action effect

f) Enzyme Reactions

g) Effect of pressure

h) Effect of enthalpy

K_eq = e^{-(D H) / RT}

For an exothermic reaction, D H has a negative value (heat is given off) so the exponent now has a negative times a negative so the exponent must be positive. If T increases, the exponent decreses, and the whole e term (and thus K_eq must decrease.

Similarly, if the heat of reaction is positive (endothermic reaction) the exponent will be negative (or an inverse). As T increases the exponent will decrease and the whole e term (since it is an inverse) will

increase. Hence K_eq must increase.

a) Oxidation Reduction

http://www.chem.uidaho.edu/~honors/redox.html

b) Reference electrode

http://www.chem.uidaho.edu/~honors/h2cell.html

c) Measuring standard voltage

http://www.chem.uidaho.edu/~honors/stdcell.html

d) Adding Half Reactions

http://www.chem.uidaho.edu/~honors/halfrxn.html