Butane is characterized by how many carbon atoms?

Butane is an alkane, which is a type of hydrocarbon that consists solely of carbon and hydrogen atoms, with all carbon-to-carbon bonds being single bonds. The molecular formula for butane is C4H10, which indicates that it contains four carbon atoms.

The structure of butane can be represented as a straight-chain molecule where each carbon is bonded to enough hydrogen atoms to satisfy the tetravalency of carbon, conforming to the general formula for alkanes, CnH(2n+2). In this case, with n equal to 4, you can confirm that it contains four carbon atoms.

This understanding of butane's structure and molecular formula directly identifies it as a four-carbon alkane, confirming that the answer provided is indeed correct.