Question

Resources Calculate the standard enthalpy change for the reaction at 25°C. Standard enthalpy of formation values can be found in this list of thermodynamic properties. 2CH,OH(g) +30,) 200,0) + 4H,069) AHin =

Answer 1

Answer:

Given balanced combustion reaction,

2 H₃COH (g) + 3 O₂ (g) $\rightarrow$ 2 CO₂ (g) + 4 H₂O (g)

By knowing Standard enthalpies of formation of each reactant and product, the standard enthalpy of the reaction is given as,

ΔH°_rxn = Σ ΔH°_f (products) − Σ ΔH°_f (reactants).

For above combustion reaction,

ΔH°_rxn = [4*ΔH°_f H₂O(g) + 2* ΔH°_f CO₂ (g)] - [2*ΔH°_f CH₃OH(g) + 3* ΔH°_f O₂ (g)]

By placing standard enthalpies of formation of H₃COH (g), O₂ (g), CO₂ (g), H₂O (g) from literature we have,

ΔH°_rxn = [4*(−241.818 kJ/mol) + 2*(−393.509 kJ/mol)] - [2*(−201.0 kJ/mol) + 3*(0 kJ/mol)]

ΔH°_rxn = - 1352.290 kJ/mol

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