Hess's Law

AP Chemistry· difficulty 3/5

N₂ + 3H₂ 2 NH₃ ΔH = -92 kJ +? bond breaking - bond formation 2N + 6H atoms

For the bond-energy cycle shown, ΔH(reaction) equals which sum?

  • A

    0 because bonds always cancel

  • B

    bonds broken + bonds formed

  • C

    (bonds broken) - (bonds formed)

    check_circle
  • D

    (bonds formed) - (bonds broken)

Explanation

Energy is required to break bonds (positive) and released when bonds form (negative): ΔH = ΣBE(broken) - ΣBE(formed).

Want 10 more like this — adaptive to your weak spots?

Related questions