Question

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

Answer 1

By following the standard enthalpy equation, you can find the answer by simply plugging in!

Make sure to always check your signs (negative and positive) when you add and subtract so your answer is correct. I hope this helps!