Question

The enthalpy of fusion of titanium is 20.9 kJ/mol. How many grams of titanium can be melted by adding 58.0 kJ of energy to the metal at its melting point?

Answer 1

Ans. Given, enthalpy of fusion of titanium = 20.9 kJ, that is 1 mol titanium requires 20.9 kJ energy to change its physical forms from solid to liquid state, i.e. melting.

Now,    

            20.9 kJ energy melts 1 mol titanium

            Or, 1 kJ -           -     (1 mol / 20.9 kJ)

            58.0 kJ -           -       1 mol / 20.9 kJ) x 58.0 kJ

                                                = 2.775 moles Ti

Mass of 2.775 moles titanium = Moles x atomic mass

                                                = 2.775 moles x (47.867 g mol^-1)

                                                = 132.830925 g

                                                = 132.83 g

Thus, 58.0 kJ energy melts 132.83 g titanium metal.