Question

A.

Select the correct structure that
corresponds to the name.
heptane
B.
CH3(CH2)4CH3

Answer 1

Only A., the stick structure with no branches and five vertices between the two endpoints.

Step-by-step explanation:

An alkane is a saturated hydrocarbon compound with no branches- just a series of carbon atoms connected with
`{\rm C}-{\rm C}` single bonds. Heptane is the name for an alkane with
`7` carbon atoms (the prefix "
`\verb!hept-!`" means "seven".)

Notice that there are only
`6` carbon atoms in the alkane with the condensed structure formula
`{\rm CH_(3)}({\rm CH_(2))_(4){\rm CH_(3)}`. The name for that structure would be hexane, not heptane.

In general, the condensed structure formula of an alkane with
`n` carbon atoms (
`n > 2`) is
`{\rm CH_(3)}({\rm CH_(2)})_(n-2) {\rm CH_(3)}`. The correct condensed structure formula for heptane (
`n = 7`) would be
`{\rm CH_(3)}({\rm CH_(2)})_(5) {\rm CH_(3)}`.

The structure in choice A is represented as a line-angle formula. As long as no letter is present in the formula, each vertex in the line-angle formula (including the endpoints) represents a carbon atom. Hence, the line-angle formula in choice A would represent a hydrocarbon with
`7` carbon atoms.

A single line denotes a single bond between atoms. All
`7` carbon atoms in this structure are thus joined in a line with
`{\rm C}-{\rm C}` single bonds. Hence, this structure denotes an alkane with
`7` carbon atoms- heptane.