Question

Lead paint commonly contained lead (II) oxide. Some of the common modern uses of lead oxide are for production of leaded glass (in some electronics and optics). Use the reactions below to calculate the standard enthalpy of reaction (in kJ) for the formation of lead (II) oxide from lead metal and oxygen gas. PbO(s) + C(graphite) ® Pb(s) + CO(g) DHo = 107 kJ 2C(graphite) + O2(g) ® 2CO(g) DHo = –222 kJ

Answer 1

PbO(s) + C(graphite) --------------> Pb(s) + CO(g)      DHo = 107 kJ

2C(graphite) + O2(g) -------------> 2CO(g)     DHo = –222 kJ

first reverse the equation 1 :

Pb(s) + CO(g)     -------------->PbO(s) + C(graphite)      DHo = -107 kJ

divide 2nd equation by 2 :

C(graphite) + 1/2 O2(g) -------------> CO(g)     DHo = – 111 kJ

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Pb (s) + 1/2 O2 (g)   -------------> PbO (s) ,    DHo = - 218 kJ