In: Chemistry
How much energy in kJ is required to fully vaporize (at temperature of boiling point = 2525C) a 270g sample of Al(s), initially at 25C?
(Enthalpy of vap = 300. kJ/mol, enthalpy of fusion = 11. kJ/mol)
(specific heat of aluminum for both solid and liquid form = 0.9 J/(K * g))
(temperature of melting point = 625C, temp of boiling point = 2525C)
no of moles of Al = W/G.M.Wt
= 270/27 = 10moles
q1 = mCT
= 270*0.9*(625-25)
= 145800J = 145.800KJ
q2 = no of moles*enthalpy of fusion
=10*11 = 110Kj
q3 = mCT
= 270*0.9*(2525-625)
= 461700J = 461.7KJ
q4 = no of moles * Enthalpy of vap
= 10*300 = 3000KJ
Total energy = q1+q2+q3+q4
= 145.8+110+461.7+3000 = 3717.5KJ