1. CE 3231 - Introduction to Environmental Engineering and Science Readings for Next Class : Section 2.5 O hio N orthern U niversity Introduction Chemistry, Microbiology & Material Balance Water & Air Pollution Env Risk Management Common Reaction Types Within environmental chemistry reactions are carried out within water or within air.

2. Lecture 6 Common Reaction Types (Chemistry III)

3. Equilibrium Review

4. Reactions Most Common Reaction Types for Environmental Engineers Hydrolysis/Dissolution Photolysis Precipitation Acid-Base Redox Complexation Gas-Liquid Transfer

5. Hydrolysis Water inserts itself into a molecule Hydrolysis Video

6. Photolysis Energy from light inserts itself into a molecule Breakdown of a chemical by photons Photosynthesis Video Photolysis Video

7. Precipitation Two dissolved molecules come together to form a solid Precipitation Rxn

8. Acid-Base Acid-base Definition – Acid: gives off H + – Base: accepts H + – conjugate acid-base pair – H 2 O can be either acid or base – Instantaneously fast reactions acid base base acid acid base Brønsted-Lowry definition Acid base example

9. Oxidation Reduction Redox Definition - transfer of electrons (change of oxidation state) Gain election(s): reduced (GER) Lose electron(s): oxidized (LEO) – slow reactions Redox Visual

10. Complexation – Coordination of 2 (or more) atoms, molecules or ions to form more stable products Complexation visuals

11. Gas-Liquid Transfer Liquid to gas transfer visuals