Answer
See answer below.
Work Step by Step
a) $S(s)+O_2(g)\rightarrow SO_2(g)$
Enthalpy of formation:
$-296.84\ kJ/mol$
Number of moles of sulfur:
$0.054\ g\div 32.06\ g/mol=1.68\ mmol$
Enthalpy change:
$-296.84\ kJ/mol\times 1.68\ mmol=-0.50\ kJ$
b) $HgO(g)\rightarrow Hg(l)+1/2\ O_2(g)$
Enthalpy of formation:
$-90.83\ kJ/mol$
Enthalpy change:
$+90.83\ kJ/mol\times 0.20\ mol=+18.17\ kJ$
c)$1/2\ N_2(g)+3/2\ O_2(g)\rightarrow NH_3(g)$
Enthalpy of formation:
$-45.90\ kJ/mol$
Number of moles of ammonia:
$2.40\ g\div 17.03\ g/mol=0.141\ mol$
Enthalpy change:
$-45.90\ kJ/mol\times 0.141\ mol=-6.47\ kJ$
d) $C(s)+O_2(g)\rightarrow CO_2(g)$
Enthalpy of formation:
$-393.509\ kJ/mol$
Enthalpy change:
$-393.509\ kJ/mol\times 0.0105\ mol=-4.13\ kJ$
