Applications of Hess’s Law (AQA A-Level Chemistry): Quizzes

Formation and combustion enthalpies

Forming 1 mole from elements in std states

Zero

$\sum (Δ_fH^\circ products) - \sum (Δ_fH^\circ reactants)$

Burning 1 mole completely in oxygen

$\sum (Δ_cH^\circ reactants) - \sum (Δ_cH^\circ products)$

You cannot burn oxygen in oxygen

Enthalpy change is independent of route

For reactions that cannot be measured directly

Thermal decomposition of $NaHCO_3$

Hydration of $MgSO_4$ and $CuSO_4$