NCEA Level 2 Organic Chemistry Practice Exam 2026 – Complete Study Guide

In the molecular formula CnH2n+2, the variable 'n' specifically denotes the number of carbon atoms present in the hydrocarbon molecule. This formula is particularly characteristic of alkanes, which are saturated hydrocarbons where each carbon atom can form four bonds. The relationship defined by CnH2n+2 shows that for every 'n' carbon atoms, there are '2n + 2' hydrogen atoms. This reflects the structure of alkanes where the maximum number of hydrogen atoms is bonded to the carbon atoms, ensuring that all carbon atoms have four bonds. Recognizing 'n' as the number of carbon atoms helps in correctly identifying the molecular formula and understanding the corresponding molecular structure.