I'm so irritated i cannot come up with the right answer. When 1662 J of heat energy is added to 45.9 g of hexane, C6H14, the temperature increases by 16.0 °C. Calculate the molar heat capacity of C6H14.
Are you converting 45.9 g hexane to mols? That is a common mistake.
1662 = mols hexane x specific heat x 16.
Solve for specific heat.