AP EAMCET Engineering 26 Apr 2017 Shift 1 Paper

The oxidation reaction of methanol to formaldehyde and water is shown below.
2CH3OH+O2→2HCHO+2H2O
The standard enthalpy change for this reaction is calculated by asing the expression shown below
ΔHraction°=∑m.ΔHf°(products) −∑n.ΔHf°(reactants)
ΔHrescion° =

1

2

[2.ΔHf°( HCHO)+2.ΔHfo(H2O)]−

1

2

[2.ΔHr°( CH3OH)+ΔHfo(O2(g))]
ΔHreaction°=

1

2

[2(−116)+2(−286)] −

1

2

[2(−239)+(0)]
=

1

2

[−232−572]−

1

2

[−478]
=−163kJ