Question

The enthalpy of the following reactions: COCl2 (g) + H2O (l)= CH2Cl2 (l) + O2 (g) delta H = 19 kJ ; HCl (g)= 1/2 H2 (g) + 1/2 Cl2 (g) delta H = 92 kJ; CH2Cl2 (l) + H2 (g) + 3/2 O2 (g) = COCl2 (g) + 2 H2O (l) delta H = -161 kJ. Use these reactions to create a reaction pathway for the reaction of chlorine with water as shown below. Then use Hess;s law to determine the enthalpy of combustion for this reaction. H2O (g) + Cl2 (g) = 2 HCl 9g) + 1/2 O2 (g) delta H degrees = _______kJ

Answer 1

COCl2 (g) + H2O (l)= CH2Cl2 (l) + O2 (g)               delta H = 19 kJ

CH2Cl2 (l) + H2 (g) + 3/2 O2 (g) = COCl2 (g) + 2 H2O (l)    delta H = -161 kJ.

-----------------------------------------------------------------------------------------------------------

H2(g) + 1/2O2(g) -----------> H2O (l)                                     deltaH    = -142Kj

2HCl (g)--------> H2 (g) + Cl2 (g)                                            delta H = 92 kJ;

----------------------------------------------------------------------------------------------------------------

2HCl(g)+1/2O2 --------> H2O + Cl2(g)                                      delta = -50Kj

H2O(g) + Cl2(g) --------> 2HCl(g) + 1/2O2(g)                           delta H = 50KJ >>> answer