Question

Predict the sign and calculate ΔS° for a reaction. Close Problem Consider the reaction H2CO(g) + O2(g)CO2(g) + H2O(l) Based upon the stoichiometry of the reaction the sign of Sºrxn should be _________ . Using standard thermodynamic data (in the Chemistry References), calculate Sºrxn at 25°C. Sºrxn = J/K•mol

Answer 1

Answer:

$\mathbf{S^0_{rxn} = -140.41 \ J/mol.K}$

Based upon the stoichiometry of the reaction the sign of Sºrxn should be negative

Explanation:

Consider the reaction:

H2CO(g) + O2(g) --------> CO2(g) + H2O(l)

Using standard thermodynamic data;

Based upon the stoichiometry of the reaction the sign of Sºrxn should be _________ . calculate Sºrxn at 25°C. Sºrxn = J/K•mol

At standard thermodynamic data

$\mathtt{S^0_{rxn} = \sum S^0 _{product} - \sum S^0 _{reactant}}$

$S^0(CO_2)$ = 213.79 J/mol.K

$S^0(H_2O)=$  69.95  J/mol.K

$S^0 ({H_2CO}) =$ 218.95 J/mol.K

$S^0 (O_2)$  = 205.2 J/mol.K

$\mathtt{S^0_{rxn} = (213.79 + 69.95) J/mol.K - (218.95+ 205.2) J/mol.K}$

$\mathtt{S^0_{rxn} = (283.74) J/mol.K - (424.15) J/mol.K}$

$\mathbf{S^0_{rxn} = -140.41 \ J/mol.K}$

Based upon the stoichiometry of the reaction the sign of Sºrxn should be negative