Advertisements
Advertisements
Question
The standard enthalpies of formation of SO2 and SO3 are −297 kJ mol−1 and −396 kJ mol−1 respectively. Calculate the standard enthalpy of reaction for the reaction: \[\ce{SO2 + 1/2O2 -> SO3}\]
Advertisements
Solution
`Δ"H"_"f"^0` (SO2) = −297 kJ mol−1
`Δ"H"_"f"^0` (SO3) = −396 kJ mol−1
\[\ce{SO2 + 1/2O2 -> SO3}\]
`Δ"H"_"r"^0` = ?
`Δ"H"_"r"^0 = (Δ"H"_"f"^0)_"compound" - sum(Δ"H"_"f")_"elements"`
`Δ"H"_"r"^0 = Δ"H"_"f"^0 ("SO"_3) - [Δ"H"_"f"^0 ("SO"_2) + 1/2 Δ"H"_"f"^0 ("O"_2)]`
`Δ"H"_"r"^0` = −396 kJ mol−1 − (−297 kJ mol−1 + 0)
`Δ"H"_"r"^0` = −396 kJ mol−1 + 297
`Δ"H"_"r"^0` = − 99 kJ mol−1
APPEARS IN
RELATED QUESTIONS
Select the most appropriate option.
If the standard enthalpy of formation of methanol is –238.9 kJ mol–1 then entropy change of the surroundings will be _______.
Answer in brief.
Obtain the expression for work done in chemical reaction.
Obtain the relationship between ΔH and ΔU for gas phase reactions.
Calculate the standard enthalpy of formation of \[\ce{CH3OH_{(l)}}\] from the following data:
\[\ce{CH3OH_{(l)} + 3/2 O2_{(g)} -> CO2_{(g)} + 2H2O_{(l)} }\]; ΔrH° = − 726 kJ mol-1
\[\ce{C_{(graphite)} + O2_{(g)} -> CO2_{(g)}}\]; ΔcH° = −393 kJ mol−1
\[\ce{H2_{(g)} + 1/2 O_{(g)} -> H2O_{(l)}}\]; ΔfH° = −286 kJ mol−1
Write the expression showing the relation between enthalpy change and internal energy change for gaseous phase reaction.
Enthalpy of neutralization is always a constant when a strong acid is neutralized by a strong base: account for the statement.
Calculate the enthalpy change for the reaction \[\ce{Fe2O3 + 3CO -> 2Fe + 3CO2}\] from the following data.
\[\ce{2Fe + 3/2O2 -> Fe2O3}\]; ΔH = −741 kJ
\[\ce{C + 1/2O2 -> CO}\]; ΔH = −137 kJ
\[\ce{C + O2-> CO2}\]; ΔH = −394.5 kJ
When 4 g of iron is burnt to ferric oxide at constant pressure, 29.28 kJ of heat is evolved. What is the enthalpy of formation of ferric oxide?
(Atomic mass of Fe = 56)
Given the bond energies N ≡ N, H – H and N – H bonds are 945, 436 and 391 kJ/mol respectively. The enthalpy of the reaction;
\[\ce{N2_{(g)} + 3H2_{(g)} -> 2NH3_{(g)}}\]
Calculate ΔU if 2 kJ heat is released and 10 kJ of work is done on the system.
