Sulfur dioxide is produced in enormous amounts for sulfuric acid production. It melts at −73.0°C and boils at −10.0°C....

Question

Its DeltaH fus is 8.619 kJ/mol, and its DeltaH vap is 25.73 kJ/mol. The specific heat capacities of the liquid and gas are 0.995 J/g.K and 0.622 J/g.K, respectively. How much heat is required to convert 4.250 kg of solid SO2 at the melting point to a gas at 60.0C?

Answer in scientific notation.

Answer 1

SO2(s) ==> SO2(g)

Step 1: melt SO2(s) at -73ºC:

q = m∆Hf = (4.250 kg)(1 mol/0.096 kg) x 8.619 kJ/mol = 381.57 kJ

Step 2: Raise temp of SO2(l) from - 73º to -10º

q = mC∆T = (4250 g)(0.995 J/gº)(63º) = 266,411 J = 266.411 kJ

Step 3: Convert SO2(l) to a gas @ -10º

q = m∆Hvap = (4.250 kg)(1 mol/0.096 kg)(25.73 kJ/mol) = 1139 kJ

Step 4: Raise temp of SO2(g) from -10º to 60º

q = mC∆T = (4250 g)(0.622 J/gº)(70) = 185,045 J = 185.045 kJ

Sum the q values:

381.57 kJ + 266.41 kJ + 1139 kJ + 185.05 kJ = 1972 kJ = heat required