Structural Formulas for Methane, Ethane, and Propane

Up here on the board, I’ve drawn three structural formulas. A structural formula is just the arrangement of different atoms of a substance. This substance is methane. The molecular makeup of methane is one carbon atom and four hydrogen atoms. We see that represented here in the structural formula. We have one carbon atom and four hydrogen atoms.

That makes sense, because this is just the arrangement of the atoms in the substance of methane. This is just a way to visually see the arrangement of atoms that are in methane. We go to this next structural formula, which is ethane. As you can guess, the molecular makeup is two carbon atoms and six hydrogen atoms, because we have two carbon atoms here and six hydrogen atoms.

Finally, we come to propane. Here, we have three carbon atoms, so we’re going to put a subscript of 3 after C. Then, we have eight hydrogen atoms, so we’re going to put a subscript of 8 after hydrogen. Those are the structural formulas for methane, ethane, and propane. A structural formula is just the arrangement of different atoms of a substance.