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Chemistry Homework Help => AP Chemistry => Topic started by: Siba on January 29, 2026, 06:06:37 PM

Title: AP chemistry Hess's Law -Born–Haber Cycle Steps
Post by: Siba on January 29, 2026, 06:06:37 PM
I want practice and a better understanding on how to compute these types of questions.
Screenshot 2026-01-29 at 6.05.31 PM.png
Title: Re: AP chemistry Hess's Law
Post by: uma on January 31, 2026, 06:25:21 AM
Born–Haber Cycle Steps:

Sublimation of Mg(s) → Mg(g)→ +150 kJ/mol

1st Ionization: Mg(g) → Mg⁺(g)→  +735 kJ/mol

2nd Ionization: Mg⁺(g) → Mg²⁺(g) → +1445 kJ/mol

Bond dissociation: F₂ →  2 F atoms  →  +154 kJ/mol

Electron affinity: 2 F(g) → 2 F⁻(g)  → 2 × (−328) = −656 kJ/mol

Lattice formation: Mg²⁺ + 2F⁻ → MgF₂(s) → −2913 kJ/mol
Total Enthalpy (ΔHf°):
Δ 𝐻 𝑓∘=
=(150+735+1445+154)−(656+2913)=2484−3569= −1085 kJ/mol
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