Use the given data and calculate the enthalpy change for the following:

a) B2O3(s)+3COCL2(g)--->2BCL3(g)+3CO2(g)

b)Hg(l) +2Ag+(aq)--->Hg2+(aq)+2Ag(s)

compound:
B2O3(s)
COCL2(g)
BCL3(g)
CO2(g)

Ag+ (aq)
Hg2+ (aq)

Delta H (standard circle)f kj/mol
-1272.8
-218.8
-403.8
-393.5

+105.6
+171.1

1 answer

a) B2O3(s)+3COCL2(g)--->2BCL3(g)+3CO2(g)

DHrxn = (sum DH products) - (sum DH reactants).
DHrxn = [(2*DH BCl3) + (3*DH CO2)] - [(DH B2O3) + (3*DH COCl2)]