Chem: Keys to PPs 5.2/5.3

Part 1: https://docs.google.com/file/d/0BycFPIaR0t9bLUpRWlZxYnpMR2c/edit?usp=sharing

Part 2: https://docs.google.com/file/d/0BycFPIaR0t9bQy1rem55WXl5SzQ/edit?usp=sharing