Question

Using tabulated thermodynamic values in the Appendix:

Calculate the minimum amount of propane that would need to be burned (at a flame temperature of 2000 °C) to raise 100 g of ice from −4 °C to the boiling point 100 °C. Assume perfect heat transfer from the reaction to the ice.

Answer 1

heat required (q) = mice*sice*DT+n*DHfus+mwater*swater*DT+

                  = 100*2.108(0--4)+(100/18)*6.01*10^3+100*4.184*(100-0)

                 = 76.072 kj

enthalpy of combustion of propane,DH0c = -2202.0 kj/mol

molarmass of propane(C3H8) = 44 g/mol

amount of propane required = 76.072/2202 = 0.0345 mol

mass of propane required = 0.0345*44 = 1.518 g