iGCSE Chemistry Section 3 Lesson 2 | PDF | Alkene | Ethanol - Scribd This document provides an overview of Section 3 (Organic Chemistry) of the iGCSE Chemistry course It focuses on lessons about alkanes, alkenes, and ethanol Key points include: - Alkanes have the general formula CnH2n+2 and form single bonds Alkenes contain a double bond and have the formula CnH2n