Cambridge O Level Chemistry · Syllabus 5070 · Organic Chemistry
Structural Formula
What is Structural Formula?
An unambiguous description of the way the atoms in a molecule are arranged, written in a condensed line of text such as CH3CH2OH, in which the connectivity is fully determined but individual bonds are not drawn.
This definition is part of the Organic Chemistry chapter in Cambridge O Level Chemistry.
Common mistakes with Structural Formula
- “The displayed formula of ethanol is CH3CH2OH.” why it fails That is a structural formula. It compresses C–H and O–H bonds into text instead of drawing them. correct A displayed formula shows every atom and every bond as a line, including the O–H bond that “OH” hides. Taught in 11.1A.
- 1. “The displayed formula of ethanol is CH3CH2OH.” defect A structural formula supplied where a displayed one was demanded. why “Displayed” is a technical requirement, not a style. Every bond must appear as a line, and “OH” hides one. repair Draw the O joined to C by a line and the H joined to that O by another: –O–H. transfer Draw the displayed formula of propan-2-ol and count the bonds. You should reach 11.
Questions students ask about Structural Formula
What is the difference between a structural formula and a displayed formula?
A structural formula is an unambiguous but condensed line of text, such as CH3CH2OH, in which the connectivity is clear but individual bonds are not drawn. A displayed formula shows every atom and every covalent bond as a line, including bonds hidden inside a condensed group such as OH — so ethanol's displayed formula must show the O-H bond explicitly, not compress it into the letters "OH".