Question

Ho ilacer e trunschpl Use Hess's Law to calculate the standard enthalpy (AHº) for the foll standard enthalpy (AH) for the following reaction inolonce to the on an C(s) + O2(g) → CO(g) given the following two equations. C(s) +502(9) – co(9) AH° = -110.5 kJ CO2(g) – CO(g) +502(9) AH° = +283.0 kJ [15]

Answer 1

According to the Hess's law

For a chemical reaction ,the net change of heat change (∆H^o ) will be same weather the process occurs in one step or several step.

Let a reaction occurs in one step

A ----- > C ∆H^o = ∆H^o

But when the reaction is occurs in two step

A -------- > B ∆H^o = ∆H₁

B--------- > C ∆H^o = ∆H _{​​​​2}

Then according to the Hess's law

∆H ^o = ∆H₁ + ∆H₂

According to the Lavoisier and Laplace law

The heat change for a reaction in forward direction is equal in the magnitude but opposite in sign the reverse reaction .

If A --- > B ∆H = y KJ

For the reverse reaction

B ----- > A ∆H = - y KJ

CCS) +029) COCg) 4HP= BHLlet) givem CCS)+02(y) COcg) -110.5 kJ Cocy) Cocg)+foc H 283.0 K by the problem C (S) +0) COcg) H-110.5KJ Cocg) + )COy H 283.0kJ CCS) + 02( -110-5-233-) K7 CO ) yH-393 5 KJ Hemce the tamdatd enthalpy H for -393. 5 KJ the reactiom