Physics I / Representations from particles to formulas
Practice question · Match the pairs

One substance, four lenses. Match each representation of ethanol to what it best reveals.

  • Molecular formula C₂H₆O
  • Structural formula CH₃–CH₂–OH
  • Ball-and-stick model
  • C₂H₆O vs. its isomer CH₃–O–CH₃
  • Which atoms bond to which
  • Same formula, different connectivity
  • 3D geometry and bond angles
  • Atom counts only, composition
Hints
  1. Each representation deliberately discards information to highlight something else.
  2. Ethanol (a drinkable liquid) and dimethyl ether (a gas) share C₂H₆O, formulas alone cannot tell them apart.
Show the answer
  • Molecular formula C₂H₆O Atom counts only, composition
  • Structural formula CH₃–CH₂–OH Which atoms bond to which
  • Ball-and-stick model 3D geometry and bond angles
  • C₂H₆O vs. its isomer CH₃–O–CH₃ Same formula, different connectivity
Why

Chemical representations trade detail for clarity: formulas count, structures connect, models shape. Isomers prove the stakes, identical formulas, different connectivity, wildly different substances.

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