Question

Copper has been used for thousands of yers, either as a pure metal or in alloys. It is frequently used today in the production of wires and cables. Copper can be obtained through smelting or recylcing. Determine the energy associated with each of these processes in order to recycle 1.06 mol Cu. The smelting of copper occurs by the balanced chemical equation:

CuO(s)+CO(g) --> Cu(s)+CO2(g)

Where deltaHfCuO is = 155/kJ/mol. Assume the process of recycling copper is simplifed to just the melting of the solid Cu starting at 25 degrees C. The melting point of Cu is 1084.5 degrees C with deltaHfus =13.0 kJ/mol and a molar heat capacity, Cp,Cu =24.5 J/mol degrees C.

Energy for recovering Cu from CuO from reaction about (answer in kJ)

Energy for recycling Cu (answer in kJ)

Answer 1

Let ΔH bet the heat energy required to convert CuO to Cu

Therefore, ΔH = [ ΔH_f (Cu) + ΔH_f(CO₂) ] - [ ΔH_f (CuO) + ΔH_f(Cu) ] = [ ( 0 -393.509) - [ (155 -110.525] KJ/mol

                        = - 437.984kJ/mol

Here moles of CuO = 1.06 mol

The required energy = 464.26kJ

The recycling copper is simplifed to just the melting of the solid Cu starting at 25 degrees C.

Let the required energy be Q.

Here, Q1 = heat required to increase the temperature from 25 degrees C to 1084.5 degrees C

                = (1.06 mol) x ( 24.5 J/mol degrees C) x (1084.5 - 25 ) degrees C

                = 27515.215 J = 27.515 kJ

        Q2 = heat required to melt copper = (1.06 mol) x (13.0) KJ = 13.78 kJ

Q = Q1 + Q2 = (27.515 + 13.78 ) kJ = 41.3 kJ