Using standard heats of formation, calculate the standard enthalpy change for the following reaction.

Question

Using standard heats of formation, calculate the standard enthalpy change for the following reaction.

Fe(s) + 2HCl(aq)FeCl2(s) + H2(g)

Answer 1

Use the following equation:

 

ΔH⁰ = ΣH_f⁰p - ΣH_f⁰R

 

where, 

 

ΔH_⁰ = standard enthalpy change of reaction

 

ΣH_f⁰p = sum of standard heat of formation for the products

 

ΣH_f⁰R = sum of standard heat of formation for the reactants

 

You can find the standard heat of formations from any chemistry textbook, and complete the calculation.

 

Don't forget to consider the coeffients in the balanced equation during your calculation.

 

 

 

 

Answer 2

You need to provide the standard heats of formation (look them up) for FeCl2((s) and H2(g) an HCl(aq). Value for Fe(s) will be zero. Then use ∑∆Hf products - ∑∆Hf reactants = ∆Hreaction Don't forget to multiply by the coefficient in the balanced equation.