Question

Given that 2S (s)+3O2 (g)→2SO3 (g)2SO2 (g)+O2 (g)→2SO3 (g) has an enthalpy change of −790.4 kJ has an enthalpy change of −198.2 kJ. What is the heat of formation of SO2 in kilojoules?S (s)+O2 (g)→SO2 (g)?

Answer 1

Answer:

The heat of formation of SO2 is -296.1 kJ

Explanation:

Step 1: Data given

2S (s)+3O2 (g)→2SO3 (g)     ΔH = -790.4 kJ  

2SO2 (g)+O2 (g)→2SO3 (g)  ΔH = -198.2 kJ

Step 2: Calculate the heat of formation of SO2

2 S(s) + 3 O2(g) --> 2 SO3(g) ΔH = -790.4 kJ  

S(s) + 3/2 O2(g) → SO3(g)    ΔH = -395.2 kJ

2SO2 (g)+O2 (g)→2SO3 (g)  ΔH = -198.2 kJ

SO3(g) → SO2(g) + 1/2 O2(g)   ΔH = 99.1 kJ

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S(s) + 3/2 O2(g) → SO3(g)    ΔH = -395.2 kJ

SO3(g) → SO2(g) + 1/2 O2(g)   ΔH = 99.1 kJ

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S (s)+O2 (g)→SO2 (g)

ΔHrxn = (-790.4 /2) kJ + (198.2/2) kJ

ΔHrxn = -395.2 kJ + 99.1 kJ = 296.1 kJ

The heat of formation of SO2 is -296.1 kJ