Learn AP Chemistry with Mr. Krug! Get the AP Chemistry Ultimate Review Packet: *Guided notes for these AP Chem videos are now included in the Ultimate Review Packet!* Find them at the start of each unit. If you need help reviewing for your other AP Courses, such as Biology, Physics 1, Environmental Science, Calculus AB, Pre-Calculus, Psychology, Macroeconomics, World History, US History, and more, check out . #apchemistry #apchem In this video, Mr. Krug shows students how to simplify the mathematics in equilibrium problems with very small equilibrium constants. This method is sometimes called the 5% rule. He works several equilibrium example problems in the video. 00:00 Introduction 00:29 Example Problem No 1 06:51 When Can You Use the 5% Rule? 08:39 Example Problem No 2 12:49 Conclusion