data below, calculate the total heat (in J) neoded to convert 0.333 mol of gascous 333 mol of
gascous ethanol at 300°C and 1 atm to liquid ethanol at 25.0°C and 1 atm: t 1 atm-78.5°C
AHP:40.5 kJ/mol hp 1.43 Jig C 245 Jg C Q17. Sulfur dioxide is produced in enormous amounts
for sulfuric acid production. It melts at-73 C and boils at -10°C. Its ??'-is 8.619 kJhnol and its
Art-s 25 73 kJ nol. The specifie heat capacities of the liquid and gas are 0.995 J/g K and 0.622
J/g K, respoctively. How much heat is required to convert 2.500 kg of solid SO, at the melting
point to a gas at 60.°C? CHEM-01A-Work Session # 12: Intermolecular Forces
Solution
Ans 16
Heat required to change the temperature from 300 to 78.5 C
Q1 = m x Cpg x (T2-T1)
= 0.333 mol x 1.43 J/gC x 46g/mol x (78.5 - 300)C
= - 4851.89 J
Phase change at 78.5 C from gas to liquid
Q2 = m x Hcon
H vaporization = - H condensation
= 0.333 mol x (- 40.5 kJ/mol)
= - 13.4865 kJ x 1000J/kJ = - 13486.5 J
Heat required to change the temperature from 78.5 to 25 C
Q3 = m x Cpl x (T2-T1)
= 0.333 mol x 2.45 J/gC x 46g/mol x (25 - 78.5)C

= - 2007.81 J
Total heat needed
= - 4851.89 - 13486.5 - 2007.81
= - 20346.2 J
Negative sign shows the release of heat during the process