Final answer:
The structural formula of butane shows the actual connections between atoms and the molecule's layout, unlike the molecular formula which only shows the number and types of atoms.
Step-by-step explanation:
The molecular formula for butane, C₄H₁₀, provides the number and type of atoms in the molecule, but does not specify how these atoms are connected or the shape of the molecule. Conversely, the structural formula shows the specific connections between atoms and the layout of the molecule. This is crucial for identifying structural isomers, such as butane and 2-methylpropane, which have the same molecular formula but different structures leading to different chemical properties.
While the molecular formula tells us there are 4 carbon atoms and 10 hydrogen atoms in butane, the structural formula goes beyond that by depicting the sequence in which these atoms are bonded. It shows us that butane has a straight-chain structure, whereas 2-methylpropane, which also has the formula C₄H₁₀, has a branched structure. This information about the arrangement of atoms within molecules like butane is vital for understanding chemical behavior and physical properties.