Use the ΔH°f information provided to calculate ΔH°rxn for the following:
ΔH°f (kJ/mol) SO2Cl2 (g) + 2 H2O(l) → 2 HCl(g) + H2SO4(l) ΔH°rxn = ?
SO2Cl2(g) -364
H2O(l) -286
HCl(g) -92
H2SO4(l) -814
Where is the answer?
To calculate ΔH°rxn for the given reaction using the ΔH°f values, you need to use the following steps:
1. Write out the equation for the reaction:
SO2Cl2 (g) + 2 H2O (l) → 2 HCl (g) + H2SO4 (l)
2. Determine the moles of each substance in the balanced equation:
From the equation, there is 1 mole of SO2Cl2, 2 moles of H2O, 2 moles of HCl, and 1 mole of H2SO4.
3. Calculate the ΔH°rxn using the ΔH°f values:
ΔH°rxn = Σ(nΔH°f products) - Σ(nΔH°f reactants)
Using the given ΔH°f values:
ΔH°rxn = [2(ΔH°f HCl) + ΔH°f H2SO4] - [ΔH°f SO2Cl2 + 2(ΔH°f H2O)]
Substituting the values:
ΔH°rxn = [2(-92 kJ/mol) + (-814 kJ/mol)] - [-364 kJ/mol + 2(-286 kJ/mol)]
Calculating the values:
ΔH°rxn = [-184 kJ/mol - 814 kJ/mol] - [-364 kJ/mol - 572 kJ/mol]
ΔH°rxn = -998 kJ/mol + 936 kJ/mol
ΔH°rxn = -62 kJ/mol
Therefore, the ΔH°rxn for the reaction is -62 kJ/mol.
To calculate ΔH°rxn for the given reaction, you need to use the ΔH°f (standard enthalpy of formation) values of the reactants and products. The standard enthalpy of formation is the change in enthalpy when one mole of a compound is formed from its constituent elements in their standard states.
ΔH°rxn can be calculated using the formula:
ΔH°rxn = Σ(nΔH°f products) - Σ(nΔH°f reactants)
where Σ represents the summation of, n represents the stoichiometric coefficient of each species in the balanced equation, and ΔH°f represents the standard enthalpy of formation.
Using the given ΔH°f values:
For the products:
- 2 HCl(g): -2 * (-92 kJ/mol) = +184 kJ/mol
- H2SO4(l): -814 kJ/mol
For the reactants:
- SO2Cl2(g): -364 kJ/mol
- 2 H2O(l): 2 * (-286 kJ/mol) = -572 kJ/mol
Now, substitute these values in the formula:
ΔH°rxn = (+184 kJ/mol + (-814 kJ/mol)) - (-364 kJ/mol + (-572 kJ/mol))
= 238 kJ/mol
Therefore, the ΔH°rxn for the given reaction is 238 kJ/mol.