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CE 3231 - Introduction to Environmental Engineering and Science. Readings for Next Class : Section 2.4. O hio N orthern U niversity. Chemistry, Microbiology & Material Balance. Introduction. Water & Air Pollution. Env Risk Management. Equilibrium and Kinetics
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CE 3231 - Introduction to Environmental Engineering and Science Readings for Next Class: Section 2.4 Ohio Northern University Chemistry, Microbiology & Material Balance Introduction Water & Air Pollution Env Risk Management Equilibrium and Kinetics How far and how fast a chemical reaction occurs makes all the difference. In today’s class we will cover the basics for writing and solving equilibrium and kinetic relationships. I will also introduce reaction order and solutions for common reaction order systems of equations.
Reactions • Equilibrium Relationships
Reactions • Rates of Reaction
Reactions • Reaction Order • Reaction rates for different reactions often follow similar mathematical forms, including: • Zero Order • First Order • Second Order • These you can solve by hand…more complex forms require advanced mathematics
Reactions • Reaction Order
The following table is a summary of important information related to 0, 1st and 2nd order reactions: Orderrateexpressionconc-time relationshiphalf-lifelinear plot 0 rate = k X0- X = k X0/2kXvst 1 rate = kX log X0/X = kt/2.30 0.693/k log Xvst 2 rate = kX2 1/x - 1/X0 = kt 1/X0k 1/Xvs t
Example Problems • Following a reaction that has reached equilibrium 0.25 molsof N2 gas and 0.43 molsof O2are left in a 1 L cylinder that contains 6.64x10-3 mols of nitric oxide gas. Assuming that one mol of N2 and one mol of O2 react to form 2 mols of NO what is the equilibrium constant for this system? • For the reaction: PCl3 + Cl2 ↔ PCl5… What is the equilibrium concentration of the product, PCl5, if the initial concentrations of the reactants are [PCl3] = [Cl2] = 0.14 M and [PCl5]o= 0 given K = 96.2 M-1