The molar heat capacity of gaseous heptane at 25.0°c is 165.2 j / (mol · °c). what is its specific heat?

Specific heat is the amount of heat required to raise the temperature of a unit mass of a substance by a unit degree. It is usually expressed as J/g C

In this case:

165.2 J of heat is required to raise the temperature of 1 mole of heptane by 1 C

1 mole of heptane (C7H16) = 100 g

Specific heat of heptane = 165.2/100 = 1.652 J/g C