Given the following standard enthalpy of combustion data, construct a Hess's Law cycle and calculate the standard enthalpy of formation of hydrogen sulfide ΔHϴf [H2S].
S(s) + H2(g) → H2S (g)
ΔHϴc sulfur = -297 kJ mol-1
ΔHϴc hydrogen= -286 kJ mol-1
ΔHϴc hydrogen sulfide = -562 kJ mol-1