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son4ous [18]
3 years ago
6

A scientist measures the standard enthalpy change for the following reaction to be 67.9 kJ:

Chemistry
1 answer:
bekas [8.4K]3 years ago
3 0

Answer: The standard enthalpy of formation  of H_2O(g) is  -252.1 kJ/mol.

Explanation:

The balanced chemical reaction is,

Fe_2O_3(s)+3H_2(g)\rightarrow 2Fe(s)+3H_2O(g)

The expression for enthalpy change is,

\Delta H=[n\times H_f_{products}]-[n\times H_f_{reactantss}]

Putting the values we get :

\Delta H=[2\times H_f{Fe}+3\times H_f{H_2O}]-[1\times H_f{Fe_2O_3}+3\times H_f{H_2}]

67.9kJ=[(2\times 0)+(3\times H_f{H_2O})]-[(1\times -824.2kJ/mol)+3\times 0kJ/mol)]

H_f{H_2O}=-252.1kJ/mol

Thus standard enthalpy of formation  of H_2O(g) is  -252.1 kJ/mol.

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