Break Costs. Form Pays.

Methane burns and your house gets warm. Almost everyone says the energy came from breaking the bonds in the fuel. That sentence is exactly backwards, and it is the single most expensive idea in Unit 6. Breaking a bond always costs. Forming one always pays. ΔH is just the difference — and because the numbers in the table are averages, it is only ever an estimate.

8 STEPS · 6 QUICK CHECKS · ΔH ≈ Σ(bonds broken) − Σ(bonds formed) · AN ESTIMATE, NOT AN EXACT VALUE · v1