a$)$ Given equations $(1)$ and $(2),$ calculate the enthalpy change for equation.

$(1)Pb($s$)+Pb{O}_2($s$)+2S{O}_3($g$)2PbS{O}_4($s$)$

$H=-775kJ$

$(2)S{O}_3(g)+H_{2}O($l$)H_{2}S{O}_4($aq$)$

$H=-133kJ$

$(3)Pb($s$)+Pb{O}_2($s$)+2H_{2}S{O}_4($aq$)2PbS{O}_4(s)+2H_{2}O(l)$

b$)$ Draw an enthalpy diagram to represent equation $(3).$