What is the number of carbon atoms in propane?

Propane is a hydrocarbon belonging to the alkane family, which means it consists solely of carbon and hydrogen atoms and has single bonds between them. The general formula for alkanes is CnH(2n+2), where "n" represents the number of carbon atoms.

For propane, which is the simplest three-carbon alkane, the "n" value is 3. Therefore, substituting 3 into the formula gives us C3H(2(3)+2), or C3H8. This indicates that propane contains exactly three carbon atoms. It is essential to recognize propane's structure: it has a linear chain of three carbon atoms, making it distinct from other hydrocarbons that have a different number of carbons, represented by the other choices. Thus, the correct number of carbon atoms in propane is indeed three.