When 1686 J of heat energy is added to 402 g of ethanol C2H6

When 1686 J of heat energy is added to 40.2 g of ethanol, C2H6O, the temperature increases by 17.1 C. Calculate the molar heat capacity of C2H6O.

Solution

Molar heat capacity (Cp) = heat energy / (mol x change in Temperature)

Molar mass of C2H5OH = 46 g/mol

Moles of C2H5OH = 40.2 g / 46 g/mol => 0.874 mol

Cp = 1686 J / (0.874 mol x 17.1 C)

Cp = 112.81 J/mol.C