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Calculate the standard reaction enthalpy for the reaction of calcite with hydrochloric acidCaCO3(s) + 2 HCl(aq) →CaCl2(aq) + H2O(ℓ) + CO2(g)The standard enthalpies of formation are: for CaCl2(aq) : −877.1 kJ/mol; for H2O(ℓ) : −285.83 kJ/mol; for CO2(g) : −393.51 kJ/mol; for CaCO3(s) : −1206.9 kJ/mol; and for HCl(aq) : −167.16 kJ/mol.1. −72.7 kJ/mol 2. −38.2 kJ/mol 3. −215 kJ/mol 4. −116 kJ/mol 5. −165 kJ/mol 6. −15.2 kJ/mol 7. −98.8 kJ/mol |
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Answer» Correct option (6) −15.2 kJ/mol Explanation: We use Hess’ Law: ∆H◦ = ∑ n ∆H◦ j,prod − ∑ n ∆H◦ j,reac = ∆H◦ f, CaCl2(aq) + ∆H◦ f, H2O(ℓ) + ∆H◦ f,CO2(g) − [ ∆H◦ f, CaCO3(s) 2 + (∆H◦ f, HCl(aq)] = −877.1 kJ/mol + (−285.83 kJ/mol) + (−393.51 kJ/mol) − [ −1206.9 kJ/mol + 2 (−167.16 kJ/mol)] = −15.22 kJ/mol . |
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